A Russian draft resolution calling for an immediate ceasefire in Ukraine and a humanitarian corridor met with criticism from the West and cool response at the Security Council Monday.

Moscow drafted the resolution at the start of its month-long presidency of the Council as Western powers want to enforce humanitarian corridors in Syria -- a prospect blocked by Russia.

NATO and Russia had a "very frank" exchange of views on the Ukraine crisis Monday but found no common ground in the first such meeting since Moscow annexed Crimea, officials said.

"I can say it was a very frank exchange of views," alliance spokeswoman Oana Lungescu said after a meeting of the NATO-Russia Council which groups the 28 member state ambassadors with their Russian counterpart.

Russia has lifted its embargo on arms supplies to Pakistan and is holding talks on supplying Islamabad with combat helicopters, the head of state-owned Rostec, Sergei Chemezov, said Monday, the ITAR-TASS news agency reported.

"Such a decision has been taken. We are holding talks on supplying the helicopters," Chemezov said, adding that the negotiations were about Russian Mi-35 Hind attack helicopters.

The United States said Monday that Russia is continuing to support the pro-Russian insurgency in Ukraine, despite U.S. sanctions aimed at punishing it for its alleged interference in its neighbor.

"There is evidence that Russia continues to allow the free flow of weapons, funds, and fighters across its borders and President (Vladimir) Putin's next steps are still not clear," Treasury Secretary Jacob Lew said, in a speech in Washington.

Russian rescuers retrieved 12 bodies while three remained missing on Monday after a helicopter carrying senior regional officials crashed into a remote northern lake.

The Mi-8 helicopter carrying 17 passengers and crew including top regional officials and businessmen, crashed into the Munozero lake in the far northern Murmansk region on Saturday. Two survived the crash.

Ukrainian forces killed five rebels on Monday while repelling an attack by 500 pro-Russian gunmen on a federal border guard camp in the strife-torn separatist east, Kiev officials said.

The border guard service said seven of its servicemen were wounded when "around 500 terrorists" attacked one of its units stationed outside the industrial city of Lugansk.

Russian President Vladimir Putin will hold face-to-face talks on the Ukraine crisis with British Prime Minister David Cameron, Downing Street said on Monday.

The two leaders will meet after they attend events to mark the 70th anniversary of the D-Day landings in Normandy, France, on Friday.

Russia will on Monday submit a draft resolution to the United Nations Security Council on creating a corridor to allow Ukrainians to escape areas affected by fighting, Russian Foreign Minister Sergei Lavrov said.

"Russia today plans to submit a draft resolution to the U.N. Security Council," Lavrov said at a televised news conference.

Crisis-hit Ukraine won a vital reprieve from Russia on Monday when Moscow pushed back a possible cut in gas shipments, which would also impact parts of Europe, until next week.

Russia's surprise decision came hours before the two sides were to lock horns in Brussels over a price dispute that emerged when Moscow cancelled the discounts it awarded the pro-Kremlin regime which was ousted in February street protests.

The leader of Georgia's breakaway region of Abkhazia, Alexander Ankvab, said on Sunday he was resigning following days of political upheaval on Russia's southern flank.

"I am resigning from the post of the president of the Republic of Abkhazia" with a view to maintaining stability in the country, he said in a statement.