Israeli Prime Minister Benjamin Netanyahu has vowed that Israel will continue its operations across the border in Syria after an F-16 fighter jet was shot down.

The Israeli warplane was hit by Syrian anti-aircraft fire on its return from a bombing raid on Iranian targets in the early hours of Saturday, launched after Israeli military say an Iranian drone penetrated its airspace. Its two crew members survived with non-life-threatening injuries.

In response, Israel launched a second ferocious raid, believed to be its most aggressive in years, which it said hit 12 Iranian and Syrian military sites.

Syrian state media did not immediately disclose any casualties or damage but the UK-based monitor Syrian Observatory for Human Rights said that at least six soldiers were killed.

Israeli fighter jet wreckage burns after being shot down following offensive against Syrian and Iranian targets

“Yesterday we landed hard blows on the forces of Iran and Syria. We made unequivocally clear to everyone that our modus operandi has not changed one bit,” Mr Netanyahu said during his weekly cabinet meeting on Sunday.

“We will continue to do whatever is necessary to protect our sovereignty and our security.”

Syria’s war is reaching its seventh anniversary – but the weekend of violence and heightened rhetoric from its many international players show that rather than slowing down, it is becoming more complicated than ever.

Inside Syria's obliterated ‘capital of the revolution’ Show all 10 1 /10 Inside Syria's obliterated ‘capital of the revolution’ Inside Syria's obliterated ‘capital of the revolution’ The reconstructed Khaled Bin al-Waleed Mosque is framed by a damaged building, in the old city of Homs AP Inside Syria's obliterated ‘capital of the revolution’ Sumaya Bairuty, 38, an English-language teacher who works in the capital Damascus, speaks with The Associated Press while as she walks to her parents house in the war-damaged Bab Dreib neighborhood of Homs AP Inside Syria's obliterated ‘capital of the revolution’ Bairuty walks to her parents house AP Inside Syria's obliterated ‘capital of the revolution’ A family that returned to live in their apartment inside a heavily damaged building hang their carpets in the sun AP Inside Syria's obliterated ‘capital of the revolution’ A car drives through a devastated part of the old city AP Inside Syria's obliterated ‘capital of the revolution’ A pigeon keeper watches his pigeons fly from the roof of his home AP Inside Syria's obliterated ‘capital of the revolution’ Two people carry goods on a bicycle in the war-damaged neighborhood AP Inside Syria's obliterated ‘capital of the revolution’ Children play football in the street AP Inside Syria's obliterated ‘capital of the revolution’ It has been almost four years since the last rebels and civilians withdrew from the remaining strongholds in the ancient heart of Homs in Syria AP Inside Syria's obliterated ‘capital of the revolution’ A man rides his bicycle past a banner showing Syrian President Bashar al-Assad AP

Though formally neutral on Syria’s civil war, Israel is believed to have carried out more than 100 strikes to prevent weaponry shipments to Hezbollah, which, along with troops belonging to Shia militias from Iran and Iraq, fights alongside Syrian President Bashar al-Assad’s troops in the multi-sided conflict.

The Lebanese militant group and its backers in Tehran do not recognise the Jewish state and have sworn its destruction.

As the Syrian conflict has evolved, so too has Iran’s political influence over the Assad government – a major worry for Israeli officials, who accuse Tehran of trying to set up new missile bases in the country.

Video alleges to show Turkish helicopter being downed in northern Syria

The downing of the Israeli aircraft has been hailed as a symbolic triumph by forces loyal to the Syrian government.

Hezbollah called the incident the “start of a new strategic phrase” which would aim to limit Israel’s air superiority in the region.

Both Russia – which supports the Syrian government – and the US, Israel’s closest ally, have urged restraint following the weekend’s violence.

The Eurasia Group, a New York-based political risk consultancy, said in a commentary that “in order to reinforce deterrence, Israeli leaders will probably assess they need to show Iran, Hezbollah and Syria they will continue to strike targets despite the risk”.