(MENAFN - Arab News) KIEV/DONETSK: US and Ukrainian officials on Thursday accused Russia of being directly involved in the Ukraine conflict after pro-Kremlin rebels seized control of a key southeastern border town where fierce clashes had been raging.
'Yesterday Russian soldiers took control of the town of Novoazovsk' Ukraine's National Security and Defense Council wrote on Twitter adding that a number of surrounding villages had also been seized.
US Ambassador to Kiev Geoffrey Pyatt also said 'an increasing number of Russian troops are intervening directly in fighting on Ukrainian territory.'
'Russia has also sent its newest air defense systems including the SA-22 into eastern Ukraine and is now directly involved in the fighting' Pyatt wrote on Twitter.
After weeks of government offensives that have seen troops push deep into the last rebel bastions in the industrial east of Ukraine the tide has turned dramatically in the four-month conflict.
Kiev called on NATO for help after a rebel counter-offensive from the southeast border with Russia appeared to smash through an army blockade around the separatist stronghold of Donetsk and threaten the government-held port city of Mariupol.
Ukraine's Prime Minister Arseniy Yatsenyuk blasted Russian President Vladimir Putin for having 'deliberately unleashed a war in Europe' and called for an emergency UN Security Council meeting a call echoed by Lithuania.
A top rebel leader Alexander Zakharchenko on Wednesday admitted Russian troops were fighting alongside his insurgents but said they were on 'holiday' after volunteering to join the battle.
There has been increasing concern in Kiev and the West of Russia's direct involvement in the conflict a charge Moscow has repeatedly denied.
The spiralling tensions come after Ukrainian president Petro Poroshenko and Putin on Tuesday held their first meeting in three months but failed to achieve any concrete breakthrough despite talk of a peace roadmap.
French President Francois Hollande warned it would be 'intolerable and unacceptable' if Russian troops were on the ground after German Chancellor Angela Merkel demanded an explanation from Putin over the reports.
European security body OSCE called a special meeting to discuss 'Russia violations in Ukraine' at 0900 GMT.
A volunteer pro-Kiev commander on Wednesday said government troops were surrounded in the key transport hub of Ilovaysk southeast of Donetsk toward the Russian border.
Ukraine's military also claimed a Russian battalion had set up its headquarters near a village in the same area.
Russian has repeatedly denie it is involved in the insurrection in the former Soviet state and Foreign Minister Sergei Lavrov said Wednesday the Kremlin was 'not interested in breaking up' Ukraine.
AFP journalists reported heavy shelling in Donetsk on Thursday with local authorities saying 11 civilians had lost their lives in 24 hours.
The United Nations estimates the conflict has killed over 2200 people and forced more than 400000 to flee since April.
AFP journalists on Wednesday saw signs of a hasty retreat by Ukrainian troops after they seemed to abandon a key road southeast of Donetsk to the Russian border.
Locals told AFP the troops left on Monday after shelling from the direction of the Russian border about 30 kilometers away.
Ukraine's military conceded that 'militants together with Russian occupants' had taken control of Starobesheve some 30 kilometers from Donetsk as well as a string of villages near Novoazovsk a town close the Russian border on the Azov Sea where clashes had raged for days.
Commander Semen Semenchenko head of the pro-Kiev volunteer 'Donbass battalion' posted on Facebook that troops were trapped by rebels in Ilovaysk and were running out of ammunition.
On Wednesday Yatsenyuk said it was time for NATO to act calling for 'practical help and... crucial decisions' when it holds a summit in Wales next week.
Russia vehemently opposes closer ties between Ukraine and NATO. Concerns that Kiev could be drawn closer into the Western security alliance are seen as the main motivation behind Russia's actions in recent months.
NATO chief Anders Fogh Rasmussen said in an interview Wednesday that the alliance was preparing a rapid response unit to deploy forces swiftly in eastern Europe in the face of what he has warned was a major Russian troop buildup.
After Tuesday's meeting with Putin Poroshenko said all sides had 'without exception' agreed to his peace plan and that he and the Russian leader had discussed the 'necessity of closing Ukraine's borders' to prevent the movement of 'equipment mercenaries and ammunition.'
But Putin insisting discussing any cease-fire was not Moscow's 'business' but an internal Ukrainian affair.
He played down reports that 10 Russian paratroopers had been captured on Ukrainian soil backing his military's claims that they had strayed across the border by accident.
But opposition media in Russia reported on hushed-up funerals for two elite paratroopers suggesting they had been killed in action in Ukraine.
A group of wives and mothers of Russian paratroopers plan to hold a rally Thursday demanding authorities pull their loved ones from Ukraine.