Ukrainian troops repelled an overnight raid by about 70 armed men on a base at Artemivsk

U.S troops arrive in Poland to take part in joint military exercises in move to reassure eastern European countries

British, Dutch and Danish fighters scrambled to intercept Russian bombers that encroached on restricted airspace

He said, however, that the U.S would need allied support to apply more sanctions

Barack Obama accused Moscow of not honoring an agreement to ease tensions and says more sanctions are 'teed up'

Russian president Vladimir Putin said attack constitutes 'a very serious crime' and warned Kiev of 'consequences'


The world may look back at this as the moment the war began between Ukraine and Russia.

There was no formal declaration of war, but heavily armed Ukrainian special forces commandos launched a dramatic assault on illegal checkpoints in the separatist-controlled town of Slovyansk and killed 'up to five' militants - with Russian president Vladimir Putin firing an ominous warning back and ordering new military drills.



The attack, which saw well-drilled commandos backed up by armoured personnel carriers and helicopters swiftly overwhelm pro-Russian gunmen, was described by Putin as 'a crime' that would have 'consequences' for Kiev.

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Patrol: A Ukrainian security force officer is deployed at a checkpoint set on fire and left by pro-Russian separatists

Attack: Ukrainian special forces take position in the eastern Ukrainian city of Slovyansk on Thursday

Assault: A member of the Ukrainian special forces takes position at an abandoned roadblock in Slavyansk

Prepared: Pro-Ukrainian self-defense units perform unarmed combat drills at their training ground outside Donetsk, Ukraine, on Thursday. The unit consists of volunteer residents of the Donetsk region to combat pro-Russian insurgents

Poised: A member of the Ukrainian special forces takes position atop an armoured personnel carrier in Slovyansk

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Armoured vehicles and a helicopter were used in the assault, with several personnel carriers driving past an abandoned rebel roadblock in flames to take up position at the entry to the town.

Ukraine's acting president Oleksander Turchinov called on Russia to pull troops back from their border, stop interfering in Ukraine's internal affairs and end its 'permanent threats and blackmail'.

He added: 'If these people have advanced to the so called "acute phase" (of confrontation with protesters), this is not an acute phase, it is just a punitive operation and it will of course incur consequences for the people making these decisions, including (an effect) on our interstate relations.'

Russian warning as Ukraine says it will 'liquidate' rebels:...

Russian President Vladimir Putin, speaking on Russian TV, said that if Kiev authorities have used the army in East Ukraine it is a very serious crime against its own people.

'During the armed clash up to five terrorists were eliminated,' it said. One person had been wounded on the side of government forces, it added.

A Ukrainian ministry statement said that an 'anti-terrorist operation' by its forces, supported by the army, removed three illegal checkpoints manned by armed groups in the northeastern part of Slovyansk.

In response to the attack Russia started new military drills near the Ukrainian border, where it has amassed a formidable array of troops and armour.

Ukrainian troops on board an armoured personnel carrier on the outskirts of Slovyansk

Turmoil: The assault came as President Obama warned Russia that new economic sanctions were 'teed up'

A member of the Ukrainian special forces crouches amid the smouldering ruins of the roadblock

Death toll: Five rebels were killed during the assault and one government soldier

Reuters journalists saw a Ukrainian detachment with five armoured personnel carriers take over a checkpoint on a road north of the city in late morning after it was abandoned by separatists who set tyres alight to cover their retreat.

The soldiers appeared disciplined and well-armed, wearing camouflage with black body armour and black helmets with riot visors, the news agency said.



However, two hours later the troops pulled back. Local militia moved in and began reinforcing the position with sandbags. It was unclear why the military had withdrawn.

The fighting was the first since acting President Oleksandr Turchynov on Tuesday ordered the resumption of military operations in east Ukraine.

A war studies academic told MailOnline that Russia's new military drills are designed to send a clear message to Kiev that if it continues to dislodge pro-Russian separatists from barricades with armed assaults, that it will intervene.

The source, who did not want to be named, said that if Ukraine continued with the use of force then 'the chances of Russia intervening militarily is very high'.



Earlier Barack Obama warned Russia that new economic sanctions are 'teed up' as U.S troops arrived in Poland to reassure Nato's eastern European members in the face of the Russian troop build-up on Ukraine's border.

Obama's threat came after he accused Moscow of failing to live up to an agreement last week to ease tensions in eastern Ukraine.



But he cautioned that the United States needs to secure the support of allies to ensure that additional economic pressure is even applied.

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Aftermath: Black smoke billows from burning tyres at a checkpoint following the attack by Ukrainian commandos

Spectacle: A group of journalists look at burning tyres at a checkpoint outside Slovyansk

Stern response: President Putin said that if Kiev had used troops against its own people then it constituted 'a very serious crime'

The fighting was the first since acting President Oleksandr Turchynov on Tuesday ordered the resumption of military operations in east Ukraine Slaviansk, a city of 130,000, has become the military stronghold of a movement seeking annexation by Moscow of the Russian-speaking, industrial regions of eastern Ukraine The Ukrainian soldiers were disciplined and well-armed, wearing camouflage with black body armour and black helmets with riot visors Surprise attack: Three heavily armed commandos move along a forested road near Slavyansk Barriers: The checkpoints were partly made from tyres Mindful: A group of Ukrainian commandos keep watch at an abandoned checkpoint, with one scanning the road ahead through a pair of binoculars Battle conditions: The dramatic assault took place amid smoke and burning debris He conceded that new sanctions may not change President Putin's geopolitical calculations.

‘There are some things the United States can do alone but ultimately it's going to have to be a joint effort, a collective effort,’ Obama said during a press conference with Japanese Prime Minister Shinzo Abe.

Obama's comments underscored the difficulties he faces in devising a response to Russia's aggressive moves on Ukraine's eastern border and the growing unrest in the country driven by pro-Russian insurgents.



He did not put a timeline on when sanctions could be applied, saying only it was a matter of days, not weeks.



Obama complained that militias and armed men continue to take over government buildings in Ukraine in defiance of Ukrainian authorities.



Pro-Russian insurgents have been especially active in eastern Ukraine in the aftermath of Russia's annexation of Ukraine's Crimean peninsula. Under an agreement struck last week in Geneva, Russia had agreed to take steps to defuse the tensions and the gunmen occupying about a dozen public buildings are supposed to disarm and go home.



Taking no chances: Ukrainian troops were backed up by helicopters and several armoured personnel carriers





Warning to Russia: President Barack Obama speaking at a joint press conference with Japanese Prime Minister Shinzo Abe at the Akasaka State Guest House in Tokyo on Thursday Obama nspects an honor guard during a welcoming ceremony at the Imperial Palace in Tokyo Warning: President Putin, pictured in Saint Petersburg, told Kiev there would be consequences for its assault ‘So far we have seen them not abide by the spirit or the letter of the agreement in Geneva,’ Obama said. If that continues, he said, ‘there will be further consequences and we will ramp up further sanctions.’



By acknowledging that he still needed cooperation from allies to impose new sanctions, Obama laid bare one of the key obstacles to presenting a united front against Russia.



Many European countries rely on Russian energy and fear that increased pressure on Moscow could hurt their own economies.



‘It's important to emphasize that throughout this process our goal has been to change Mr. Putin's calculus, that our preference is to resolve this diplomatically, that sanctions hurt Russia more than anybody else but they are disruptive to the global economy,’ Obama said.

Putin said on Thursday that sanctions were hurting the Russian economy but that the damage was not critical.

‘Overall they are causing (damage), because (credit) ratings are being reviewed, loans could become more expensive and so forth. But this is of no critical character,’ Putin said of sanctions imposed over Russia's annexation of Crimea.

Putin also condemned the use of sanctions as an instrument of interstate policy on Thursday, saying they damage all concerned and reflect badly on those who impose them.

‘Overall they are harmful for everyone, they destroy the global economy (and) are dishonourable on the part of those who use those types of tools,’ Putin said.

During the same talk he also denounced the internet as 'a CIA project' and made comments about Russia's biggest search engine Yandex, sending the company's shares plummeting.



The Kremlin has been anxious to exert greater control over the Internet, which opposition activists - barred from national television - have used to promote their ideas and organize protests.



Russia's parliament this week passed a law requiring social media websites to keep their servers in Russia and save all information about their users for at least half a year. Also, businessmen close to Putin now control Russia's leading social media network, VKontakte.



Putin said that the Internet originally was a 'CIA project' and 'is still developing as such'.



To resist that influence, Putin said, Russia needs to 'fight for its interests' online.

Guard duty: A pro-Ukrainian self defense volunteer controls a road on the outskirts of Donetsk, Ukraine, on Thursday





Tensions: Pro-Russian activists guard a barricade at the regional administration building in Donetsk, Ukraine, on Wednesday

Tensions between Russia and the West increased further on Wednesday when two Russian bombers flew half a mile inside Holland’s airspace.



The Dutch scrambled F-16s to intercept the TU-95 Bears after they encroached into their airspace over the North Sea.



The jets, from Volkel air force base, escorted the bombers back into international air space.



Standing guard: A pro-Russian masked gunman patrols a street in the center of Slovyansk, eastern Ukraine

In memory: A child embraces one of the 107 wooden crosses in Prague which honour victims of the recent protests in Ukraine

Jets from Britain and Denmark were also scrambled when radar detected the bombers approaching. The Royal Air Force sent up Typhoon fighters stationed at Leuchars air base in Scotland, but the MoD refused to specify how many. An MoD spokesman said: 'Typhoon quick reaction alert aircraft were launched from RAF Leuchars to determine the identity of unknown aircraft that approached the Nato air policing area north of Scotland and could not be identified by other means. 'The aircraft were subsequently identified as Russian military aircraft. The Russian military aircraft remained in international airspace at all times as they are perfectly entitled to do so.'



Major Wilko Ter Horst, from the Dutch air force, said: ‘That's why we scrambled, that's why the Danish scrambled and the English scrambled, to ensure they fly out of our airspace.'



Anders Fridberg, spokesman for the Danish Defense Command, said the Russian planes came in from the north.

Scrambled: The Dutch air force sent F-16s to intercept two Russian bombers that encroached on its airspace

Seen off: The two TU-95 bombers were escorted back into international airspace. Pictured are three of the planes in formation over Moscow's Red Square during a parade in 2010 Precaution: The RAF scrambled an unknown number of Typhoon fighters to intercept a Russian military bomber on Wednesday ‘We just followed them and just turned back when we reached Germany,’ he said.

The Dutch ministry statement said such incidents have occurred before, citing one from March 21 and another from September 10 last year.



It has also been revealed that one of the Royal Navy’s state-of-the-art destroyers has been shadowing a ship from the Russian Navy as it travels south past Britain.

HMS Dragon, a Type 45 destroyer, began monitoring the Vice Admiral Kulakov as it approached waters north of Scotland.



The Ministry of Defence said HMS Dragon’s deployment was a ‘standard’ procedure.



U.S troops, meanwhile, have arrived in Poland to take part in joint military exercises, a move by Washington to reassure eastern European allies worried about Russia's build-up of troops on Ukraine's border.



Monitoring: HMS Dragon (in the background) accompanying the Russian destroyer Vice Admiral Kulakov at sea off Britain Protection: The Dragon's patrol area includes all the waters of the UK important to fishing and commerce as well as the UK's oil and gas production facilities around the coastline Powerful: HMS Dragon is one of the Royal Navy's most capable warships Pact: U.S. paratroopers from the U.S. Army's 173rd Infantry Brigade Combat Team based in Italy march as they arrive to participate in training exercises with the Polish army in Swidwin United front: Polish soldiers (left) accompany U.S Airborne soldiers upon their arrival at Swidwin, northern Poland Formation: Members of the 173rd Airborne Brigade march past a Polish paratrooper unit after a ceremony upon the U.S. troops' arrival One hundred and fifty soldiers from the 173rd Airborne Brigade touched down in Swidwin from their base in Vicenza, Italy, with 450 more due in a matter of days.

They will also take part in military exercises in Lithuania, Latvia and Estonia.



The troops arrived as the Russian foreign minister warned that attacks on Russian citizens or interests in Ukraine would bring a firm response. Foreign Minister Sergey Lavrov compared the circumstances to those that triggered the war with Georgia in 2008.



In Russia, Lavrov on Wednesday declared that attacks on Russian citizens are attacks against the Russian federation. His comments came day after Ukraine announced it was re-launching a campaign against pro-Russia insurgents occupying government facilities in the mostly Russian-speaking east.

Line-up: Members of a Polish paratrooper unit assemble prior to the arrival of soldiers of the U.S. Army 173rd Airborne Brigade ‘If we were attacked we could certainly respond,’ Lavrov said.



The Ukrainian government said troops repelled an overnight raid on a base at Artemivsk, between Donetsk and Slaviansk, in eastern Ukraine on Thursday.



A soldier was wounded in the attack by about 70 people who Interior Minister Arsen Avakov said on Facebook were led by Russian soldiers. Casualty details for the attackers were not clear, he said.



Avakov also said pro-Russian protesters had left the town hall in Mariupol, an industrial city on the Black Sea coast, and the mayor was back in his office - meeting the agreements made with Russia at a Geneva meeting a week ago.

The coffin of Donetsk deputy Volodymyr Rybak is carried during his funeral in the village of Horlivka, in eastern Ukraine. The Ukrainian town councillor was apparently kidnapped and tortured by pro-Russians Heartache: The wife (left) of Mr Rybak mourns next to his coffin during the funeral

Elena, the widow of slain council man Volodymr Rybak caresses the face of her husband as his body lays in the coffin prior to his funeral

Volodymr Rybak's wife Elena breaks down in tears at the funeral of her husband

On Thursday a breakaway leader in Ukraine called for Russian troops to police controversial referendums in two regions which threaten to further smash apart the country ahead of its Western-backed presidential election on 25 May.

The leader of the breakaway ‘people's republic’ of Donetsk said that 3.5 million people would be given the chance to vote for the region to be a separate state on or by 11 May.



A similar poll in neighbouring Lugansk is expected to be held on the same day also in defiance of the pro-Western government in Kiev.

Head of the Donetsk breakaway administration Denis Pushilin, whose pro-Moscow forces hold key government buildings in the industrial region, said he would welcome Russian troops to assure the referendum was held without trouble.

This happened in Crimea before the region voted in a disputed poll to join Russia.



Denying Vladimir Putin's troops were already on the ground in eastern Ukraine, as the West allege, he urged Putin to send them to police the referendums.

‘It would be easier with them as they would speed up holding of a referendum and would ensure it to be within a legal framework,’ said Pushilin.

‘A referendum will be held no later than on May 11 and it is highly probable that Lugansk will also hold it with us,’ he announced.



‘Lugansk just has to confirm similar wording of the question. Our question is as follows, ‘Do you support state independence of the Donetsk People's Republic?’

If he obtains a 'yes' vote, he claims Donetsk could then decide whether to establish federal relations either with Russia or Ukraine ‘or to stay an independent republic which is certainly hardly probable, but there will be such opportunity’.

The West sees the referendums as cynical and illegal devices to drive these pro-Moscow regions towards Russia.

Kiev has threatened to ‘liquidate’ separatist supporters occupying government offices and police stations in eastern Ukraine, but has so far failed to strike.

Ukraine, a former Soviet republic, slipped into unrest late last year when Moscow-backed President Viktor Yanukovich rejected a pact to build closer ties with Europe. Protesters took over the centre of Kiev, eventually forcing him to flee in February.

Days later, Russian troops seized control of Ukraine's Crimea Peninsula. Moscow then annexed the region, saying it was protecting Russian residents, while the West called the action an illegal land grab.