Syrian troops are now set up in positions on the Lebanese side of the border between the two countries in their battle to destroy al-Qaeda in the towering mountains of Qalamoun. Corpses rot on the mountainsides here as the Lebanese Hezbollah – fighting now inside Syria – prepare for a final struggle against the Islamists, who are today surrounded on a towering black stone peak to the north. From the heights of the Karra mountain, 7,000 feet above the Syrian-Lebanese border, I could see Syrian troops encamped on top of the two mountains – inside Lebanon.

The Syrian commander in Qalamoun, General Median Abad, tells the truth without hesitation. “Yes, we have our soldiers at two points inside Lebanon – above the frontier road which Nusrah [al-Qaeda] used to enter the Lebanese town of Ersal. Our men are on the Lebanese mountains of al-Sharqia and al-Valilal. You can see their tents.” And sure enough, across the narrow wadi (ravine) which separates us from Lebanon, I can make out the cluster of grey Syrian military tents spread across the top of the two Lebanese hills. The general confirms that he communicates with the Lebanese army – whose tank fire against Nusrah he distantly hears across the valleys – through the Hezbollah, whose forces joined him in attacking al-Karra.

General Median Abad, Syrian commander in Qalamoun (Nelofer Pazira)

Walking around its soaring heights after the battle, which ended only five days ago, is a dizzying experience. The stench of still unburied Isis bodies, the blast of mountain air tearing at the sandbags across the bleak trenches and earthworks erected by Isis before their last stand, and the network of tunnels – dug through the living rock by the Islamist defenders in the vain hope of withstanding Syrian air attacks – show just how fiercely this battle was fought. Not one Isis fighter survived – which tells its own story – although a remarkable video taken by the victors during the struggle shows a Hezbollah guerrilla telling a dying Nusrah man who is covered in blood: “God be with you” – a remarkable blessing to a dying Sunni from a Shia fighter.

World news in pictures Show all 50 1 /50 World news in pictures World news in pictures 14 September 2020 Japan's Prime Minister Shinzo Abe, Chief Cabinet Secretary Yoshihide Suga, former Defense Minister Shigeru Ishiba and former Foreign Minister Fumio Kishida celebrate after Suga was elected as new head of the ruling party at the Liberal Democratic Party's leadership election in Tokyo Reuters World news in pictures 13 September 2020 A man stands behind a burning barricade during the fifth straight day of protests against police brutality in Bogota AFP via Getty World news in pictures 12 September 2020 Police officers block and detain protesters during an opposition rally to protest the official presidential election results in Minsk, Belarus. Daily protests calling for the authoritarian president's resignation are now in their second month AP World news in pictures 11 September 2020 Members of 'Omnium Cultural' celebrate the 20th 'Festa per la llibertat' ('Fiesta for the freedom') to mark the Day of Catalonia in Barcelona. Omnion Cultural fights for the independence of Catalonia EPA World news in pictures 10 September 2020 The Moria refugee camp, two days after Greece's biggest migrant camp, was destroyed by fire. Thousands of asylum seekers on the island of Lesbos are now homeless AFP via Getty World news in pictures 9 September 2020 Pope Francis takes off his face mask as he arrives by car to hold a limited public audience at the San Damaso courtyard in The Vatican AFP via Getty World news in pictures 8 September 2020 A home is engulfed in flames during the "Creek Fire" in the Tollhouse area of California AFP via Getty World news in pictures 7 September 2020 A couple take photos along a sea wall of the waves brought by Typhoon Haishen in the eastern port city of Sokcho AFP via Getty World news in pictures 6 September 2020 Novak Djokovic and a tournament official tends to a linesperson who was struck with a ball by Djokovic during his match against Pablo Carreno Busta at the US Open USA Today Sports/Reuters World news in pictures 5 September 2020 Protesters confront police at the Shrine of Remembrance in Melbourne, Australia, during an anti-lockdown rally AFP via Getty World news in pictures 4 September 2020 A woman looks on from a rooftop as rescue workers dig through the rubble of a damaged building in Beirut. A search began for possible survivors after a scanner detected a pulse one month after the mega-blast at the adjacent port AFP via Getty World news in pictures 3 September 2020 A full moon next to the Virgen del Panecillo statue in Quito, Ecuador EPA World news in pictures 2 September 2020 A Palestinian woman reacts as Israeli forces demolish her animal shed near Hebron in the Israeli-occupied West Bank Reuters World news in pictures 1 September 2020 Students protest against presidential elections results in Minsk TUT.BY/AFP via Getty World news in pictures 31 August 2020 The pack rides during the 3rd stage of the Tour de France between Nice and Sisteron AFP via Getty World news in pictures 30 August 2020 Law enforcement officers block a street during a rally of opposition supporters protesting against presidential election results in Minsk, Belarus Reuters World news in pictures 29 August 2020 A woman holding a placard reading "Stop Censorship - Yes to the Freedom of Expression" shouts in a megaphone during a protest against the mandatory wearing of face masks in Paris. Masks, which were already compulsory on public transport, in enclosed public spaces, and outdoors in Paris in certain high-congestion areas around tourist sites, were made mandatory outdoors citywide on August 28 to fight the rising coronavirus infections AFP via Getty World news in pictures 28 August 2020 Japanese Prime Minister Shinzo Abe bows to the national flag at the start of a press conference at the prime minister official residence in Tokyo. Abe announced he will resign over health problems, in a bombshell development that kicks off a leadership contest in the world's third-largest economy AFP via Getty World news in pictures 27 August 2020 Residents take cover behind a tree trunk from rubber bullets fired by South African Police Service (SAPS) in Eldorado Park, near Johannesburg, during a protest by community members after a 16-year old boy was reported dead AFP via Getty World news in pictures 26 August 2020 People scatter rose petals on a statue of Mother Teresa marking her 110th birth anniversary in Ahmedabad AFP via Getty World news in pictures 25 August 2020 An aerial view shows beach-goers standing on salt formations in the Dead Sea near Ein Bokeq, Israel Reuters World news in pictures 24 August 2020 Health workers use a fingertip pulse oximeter and check the body temperature of a fisherwoman inside the Dharavi slum during a door-to-door Covid-19 coronavirus screening in Mumbai AFP via Getty World news in pictures 23 August 2020 People carry an idol of the Hindu god Ganesh, the deity of prosperity, to immerse it off the coast of the Arabian sea during the Ganesh Chaturthi festival in Mumbai, India Reuters World news in pictures 22 August 2020 Firefighters watch as flames from the LNU Lightning Complex fires approach a home in Napa County, California AP World news in pictures 21 August 2020 Members of the Israeli security forces arrest a Palestinian demonstrator during a rally to protest against Israel's plan to annex parts of the occupied West Bank AFP via Getty World news in pictures 20 August 2020 A man pushes his bicycle through a deserted road after prohibitory orders were imposed by district officials for a week to contain the spread of the Covid-19 in Kathmandu AFP via Getty World news in pictures 19 August 2020 A car burns while parked at a residence in Vacaville, California. Dozens of fires are burning out of control throughout Northern California as fire resources are spread thin AFP via Getty World news in pictures 18 August 2020 Students use their mobile phones as flashlights at an anti-government rally at Mahidol University in Nakhon Pathom. Thailand has seen near-daily protests in recent weeks by students demanding the resignation of Prime Minister Prayut Chan-O-Cha AFP via Getty World news in pictures 17 August 2020 Members of the Kayapo tribe block the BR163 highway during a protest outside Novo Progresso in Para state, Brazil. Indigenous protesters blocked a major transamazonian highway to protest against the lack of governmental support during the COVID-19 novel coronavirus pandemic and illegal deforestation in and around their territories AFP via Getty World news in pictures 16 August 2020 Lightning forks over the San Francisco-Oakland Bay Bridge as a storm passes over Oakland AP World news in pictures 15 August 2020 Belarus opposition supporters gather near the Pushkinskaya metro station where Alexander Taraikovsky, a 34-year-old protester died on August 10, during their protest rally in central Minsk AFP via Getty World news in pictures 14 August 2020 AlphaTauri's driver Daniil Kvyat takes part in the second practice session at the Circuit de Catalunya in Montmelo near Barcelona ahead of the Spanish F1 Grand Prix AFP via Getty World news in pictures 13 August 2020 Soldiers of the Brazilian Armed Forces during a disinfection of the Christ The Redeemer statue at the Corcovado mountain prior to the opening of the touristic attraction in Rio AFP via Getty World news in pictures 12 August 2020 Young elephant bulls tussle playfully on World Elephant Day at the Amboseli National Park in Kenya AFP via Getty World news in pictures 11 August 2020 French Prime Minister Jean Castex is helped by a member of staff to put a protective suit on prior to his visit at the CHU hospital in Montpellier AFP via Getty World news in pictures 10 August 2020 Locals harvest their potatoes as Mount Sinabung spews volcanic ash in Karo, North Sumatra province, Indonesia Antara Foto/Reuters World news in pictures 9 August 2020 Doves fly over the Peace Statue at Nagasaki Peace Park during the memorial ceremony held for the 75th anniversary of the atomic bombing EPA World news in pictures 8 August 2020 Anti-government protesters try to remove concrete wall that installed by security forces to prevent protesters reaching the Parliament square, during a protest against the political elites and the government after this week's deadly explosion in Beirut AP World news in pictures 7 August 2020 A protester throws a stone towards Israeli forces in the village of Turmus Aya, north of Ramallah in the occupied West Bank, following a march by Palestinians against the building of Israeli settlements AFP via Getty World news in pictures 6 August 2020 A woman yells as soldiers block a road for French President Emmanuel Macron's visit the Gemmayzeh neighborhood. The area in Beirut suffered extensive damage from the explosion at the seaport AP World news in pictures 5 August 2020 Damage at the site of Tuesday's blast in Beirut's port area, Lebanon Reuters World news in pictures 4 August 2020 A large explosion in the Lebanese capital Beirut. The blast, which rattled entire buildings and broke glass, was felt in several parts of the city AFP via Getty World news in pictures 3 August 2020 A general view shows the new road bridge in Genoa, Italy ahead of its official inauguration, after it was rebuilt following its collapse on August 14, 2018 which killed 43 people Reuters World news in pictures 2 August 2020 Empty stall spaces are seen hours before a citywide curfew is introduced in Melbourne, Australia EPA World news in pictures 1 August 2020 People take part in a demonstration by the initiative "Querdenken-711" with the slogan "the end of the pandemic - the day of freedom" to protest against the current measurements to curb the spread of COVID-19 in Berlin, Germany AFP via Getty World news in pictures 31 July 2020 Pilgrims circumambulating around the Kaaba, the holiest shrine in the Grand mosque in Mecca. Muslim pilgrims converged today on Saudi Arabia's Mount Arafat for the climax of this year's hajj, the smallest in modern times and a sharp contrast to the massive crowds of previous years Saudi Ministry of Media/AFP World news in pictures 30 July 2020 The Mars 2020 Perseverance mission lifts off at the Kennedy Space Centre in Florida. The mission is part of the USA's largest moon to Mars exploration. Nasa will attempt to establish a sustained human presence on and around the moon by 2028 through their Artemis programme EPA World news in pictures 29 July 2020 A woman refreshes herself in a outdoor pool in summer temperatures in Ehingen, Germany dpa via AP World news in pictures 28 July 2020 Malaysia's former prime minister Najib Razak speaks to the media after he was found guilty in his corruption trial in Kuala Lumpur AFP via Getty World news in pictures 27 July 2020 North Korean leader Kim Jong Un poses for a photograph after conferring commemorative pistols to leading commanding officers of the armed forces on the 67th anniversary of the "Day of Victory in the Great Fatherland Liberation War". Which marks the signing of the Korean War armistice KCNA via Reuters

Aboard a pick-up truck, a Syrian officer is opening the khaki body bags of three dead Isis men in a hopeless attempt to identify them. The corpses are swollen in the 46 degree heat, black with corruption, in one case wearing only underclothes. The Syrian troops and Hezbollah fighters watching from a few feet away, many holding their hands to their faces, are unfazed. Theirs was a joint operation against Nusrah – their command centre is in a single storey villa in the village of Fleita – and they say they suffered only wounded in the battle. Doctors on the heights have a medical tent with “Iranian Red Crescent” printed on the side – but there appear to be no Iranians here.

“The Syrian army and the Hezbollah fought for this mountaintop along with the [part-time] national defence forces but it was the Syrian and Hezbollah Special Forces who carried out the battle,” 48-year-old General Abad says. “For us, Hezbollah is a fighting school. We learned from their experience and we taught each other, we were literally training together as we fought and of course we had our artillery.” Syrian army guns and anti-aircraft weapons are spread over the mountains – and one zealous driver has even managed to drive a Russian-made battle tank all the way up thousands of feet of the crumbling rock track to the top of al-Karra.

A Syrian officer identifies three dead Isis fighters in body bags at the captured Qalamoun fortress (Nelofer Pazira)

The Lebanese Hezbollah commander, a short-bearded, grey haired and bespectacled man from southern Lebanon who says he is 37 – I know his home town well but suspect he is older than he claims – sat on my right during the soldiers’ lunch under canvas, a meal somewhat tempered by the bodies a few metres away and the insistence of a Hezbollah intelligence officer who filmed my every mouthful of rice and chicken. What the Hezbollah in Beirut, who know me, will make of this video nonsense I have no idea.

But the Hezbollah and Syrian soldiers sat together around the tent and appeared to know each other well, and the Hezbollah officer and his fighters share the thick and intimidating “meta” tea – made from Argentinian leaves – which is a mainstay of all Syrian military meals. Several of the Hezbollah men carried new sniper rifles but most were armed with the familiar Kalashnikovs used by the Syrian army. Their light brown kitty-litter camouflage uniforms were quite distinct from the green and brown battledress of the Syrians.

Isis militants thrown to their deaths in graphic video

To the north stands the last Isis fortress. Its defenders lie under black tents and, just to the south and lower down, their future Hezbollah attackers have spread their white tents on the mountainside. There will be more artillery fire – and more airstrikes – in the next few days, according to General Abad. His mountain eyrie will prove to be a perfect vantage point to watch the attack; al-Karra stands 7,020 feet above sea level – the Israeli emplacements on Mount Herman in the Golan Heights to the south are scarcely 2,000 feet higher, and Abad agrees that the Syrians will never leave al-Karra – which is, of course, just inside Syria, now that they have installed themselves on this peak. Military radio aerials already wave like blown wheat above the rocks.

Across to the south-west I could see the Lebanese town of Ersal – once briefly invaded by Isis and Nusrah. Some of its Lebanese military defenders had their throats cut; others – at least nine – are still held captive somewhere in these mountains, probably on the Lebanese side of the border.

Isis dug deep tunnels into the living rock to defend their mountain fortress (Nelofer Pazira)

Lebanese troops have raided Syrian refugee camps near Ersal. In their most recent operation, two men blew themselves up, but four others then died in Lebanese custody, suffering – according to the army in Beirut – from already existing “medical problems”. A likely story, as we say, but neither the Lebanese nor the Syrians cared very much.

Nusrah and Isis are now facing total defeat in Qalamoun, and the Syrian army and Hezbollah and the Lebanese army earnestly wish to bring this about. Their elimination will end the Isis threat to the Hezbollah’s supply line down the Hermel-Baalbek highway inside Lebanon and restore secure Lebanese sovereignty to the town of Ersal. The West’s diplomats have been observing this last battle from the Lebanese side of the frontier but of course they cannot come to Syria – and apparently do not realise that Syrian troops are inside Lebanese territory, albeit by only a few hundred metres.

The only Western witness to the Syrian side of the mountain conflict is The Independent, and General Median Abad gave a tactician’s description of the landscape. To the south, around the towns of Zabadani, Bloudan and Madaya, a ceasefire existed between the Syrians on one side and Nusrah and their allies on the other, “reconciliation” talks which may hand the towns back to Syrian control. If they are successful – and the imminent attack on Isis from al-Karra proves victorious – then the entire Syrian-Lebanese border will be clear of Islamists who have frequently fled into Lebanon to avoid Syrian capture and used Lebanon as a military supply route – via Ersal – into Syria.

The area around “Jurd” Ersal – the bare countryside about the town – covers 150 square kilometres of rock, scrub and wind-blasted mountains that lie across both Lebanon and Syria, separated by the narrow dirt frontier track which lies only 500 metres below us.

The narrow frontier road in the valley marks the border between Syria (left) and Lebanon (right of the road) in the Qalamoun battlefield (Nelofer Pazira)

It is a deceptively peaceful trail, drawn – of course – in some French drawing room when the French mandate authorities were dividing up Lebanon from Syria in the early 1920s. It may have made sense in a Paris salon but up on al-Karra, it seems a quixotic creation, full of political and military traps. Perhaps that is what the French intended all those decades ago.

General Abad has a less subtle view of current events. President Bashar al-Assad had early on realised the “international plot” to destroy Syria and the Hezbollah and the resistance – which is why coordination began between Syria, Iran and the Hezbollah, he explained. Israel was the “main supporter of the terrorists”, which was why it attacked Syrian and Hezbollah forces – and why Qatar and Saudi Arabia assisted in this “conspiracy”. “We hear Turkish and Saudi and Qatari voices on the terrorist radios, also Afghan voices speaking bad Arabic,” the general says. “It was after Hezbollah’s victory over Israel in Lebanon in 2006 that many people wanted to disarm Hezbollah as part of the project for a “new” Middle East of [then US Secretary of State] Condoleezza Rice. People in Lebanon were calling for the disarmament and others were trying to take Syria outside the “resistance track”. But we struggled against this – and can now fight Daesh together.”

But Isis will fight back. From their final black mountain stronghold to the north, they are still flying their miniature toy drones southwards towards the Syrian and Hezbollah lines. Further south-east, the Hezbollah and Syrian trucks grind up the mountain road past local farmers and their sons, who are picking fruit from the hanging cherry trees. They hand them to the soldiers as they pass. “The government helped them plant these trees – so why did they give their support to Nusrah when it was here?” Abad asks cheerlessly.