Russia: Turkey 'preparing to invade Syria'

Russia's defence ministry on Thursday accused Turkey of actively preparing to invade Syria as recriminations flew following a bitter breakdown in peace talks.

"We have serious grounds to suspect Turkey is in intensive preparations for an armed invasion of the territory of a sovereign state - the Syrian Arab Republic," the ministry said in a statement.

Ties between Moscow, which supports the regime of Syrian President Bashar Assad, and Ankara, which is a staunch backer of the opposition, have been in tatters since Turkey shot down a Russian bomber on the Syrian border in November.

Moscow's claims came as Turkish Prime Minister Ahmet Davutoglu, speaking at an international aid conference for Syria in London, implicitly accused Russia of "war crimes" in the country.

Ankara said earlier on Thursday that it had refused to allow a Russian reconnaissance plane to overfly its territory near Syria because of a disagreement over the flight plan.

Russia said Turkey had not given Moscow any clear explanation for the decision. "We consider these Turkish actions to be a dangerous precedent and an attempt to conceal illegal military activities at the Syrian border," the defence ministry said.

"Moreover, we are recording more and more signs of covert preparations by the Turkish armed forces for active action on Syrian territory," it said, adding that Russia has ramped up reconnaissance in the Middle East.