The Kremlin said Friday Moscow has not yet found any moderate rebels it could support in Syria, after Bashar Assad reportedly told Russia he was ready to talk to armed rebels.

This week President Vladimir Putin hosted Syria's embattled leader for a surprise summit at the Kremlin, Assad's first known foreign trip since unrest erupted in his country in 2011.

At least 14 civilians, nearly half of them children, were killed on Friday in air strikes on a flashpoint town in central Syria, a monitoring group said.

Six children and five women were among those killed in the aerial attack on Talbisseh in Homs province, according to Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.

Top diplomats from Russia, the U.S., Saudi Arabia and Turkey on Friday failed to make any major breakthrough on how to end the Syrian conflict, with the sides sharply at odds on the future of Bashar Assad.

But Moscow did seem to make progress with getting some more regional players on side, announcing with Jordan that the two countries would begin to "coordinate" their air operations over Syria. 

At least 13 people including medical staff were killed when Russian warplanes struck a field hospital in northwestern Syria, the Syrian Observatory for Human Rights said Wednesday.

"Thirteen people were killed in Russian air strikes on Tuesday on a field clinic in the town of Sarmin, including a physiotherapist, a guard, and civil defense member," the Observatory's Rami Abdel Rahman told AFP.

Syria's embattled President Bashar Assad traveled to Moscow for his first known foreign trip since the conflict broke out in his country in 2011, holding key talks on the crisis with President Vladimir Putin.

Assad, who last visited Russia in 2008, used the surprise visit on Tuesday evening to thank Putin for launching a campaign of air strikes in Syria last month, with the two leaders agreeing that military operations must be followed by political steps.

Ukrainian forces and pro-Russian insurgents said Tuesday they had begun withdrawing tanks and smaller weapons from the frontline splitting the devastated Donetsk region in the ex-Soviet state's eastern war zone.

The pullback follows similar arms movements in the smaller separatist Lugansk province and falls in line with the terms of a new truce agreement struck by the warring sides on September 1.

Three portraits of former Soviet dictator Joseph Stalin are on display in the center of Donetsk, the rebel capital of eastern Ukraine, as the separatist authorities fuel a mood of Soviet nostalgia.

The portraits, adorning a main square, seem to go down well with one young woman walking past.

Russian Prime Minister Dmitry Medvedev said Saturday that Russia is fighting for its national interests in Syria, not for President Bashar Assad.

"Of course we are not fighting for specific leaders, we are defending our national interests, on the one hand," Medvedev said in an interview to air on state television.

Dutch Foreign Minister Bert Koenders on Friday accused Russia of "sowing confusion" about the fate of flight MH17 by constantly criticizing a final report into the disaster.

"I get the impression that the Russians at this point are not really that interested in the final report, but rather in sowing confusion (about it)," Dutch media quoted Koenders saying ahead of a weekly cabinet meeting in The Hague.

Russian President Vladimir Putin on Friday warned violence in Afghanistan could spill over into ex-Soviet Central Asia, a day after the U.S. announced it would keep thousands of troops in the conflict-wracked country.

At a meeting in Kazakhstan, Putin and the leaders of ex-Soviet states agreed to create a joint task force to defend the region's borders in the event of a crisis.