Russian President Vladimir Putin has warned leaders of Central Asian nations of a possible militant incursion from Afghanistan.

Speaking at a summit of the heads of former Soviet republics Putin said on Friday the situation in Afghanistan is "close to critical" and called on his counterparts to be prepared to act together to repel a possible attack.

Putin has also praised his own military for airstrikes on the Islamic State group in Syria, saying that they destroyed dozens of command centers and killed hundreds of militants.

Putin's statement comes a day after U.S. President Barack Obama announced plans to keep about 9,800 U.S. troops in place in Afghanistan through most of next year to continue counterterrorism missions and advise Afghans battling a resurgent Taliban.