Russian President Vladimir Putin and Turkish leader Recep Tayyip Erdogan on Friday expressed grave concern over the situation in Syria's Idlib province after 33 Turkish soldiers were killed by Syrian fire, the Kremlin said.

The Kremlin added that the two also agreed in a telephone call on the need for "additional measures" and are looking into the possibility of a summit meeting in the near future. "Serious concern was expressed over an escalation of tensions in Idlib which lead to numerous casualties including among the Turkish military," the Kremlin said.

Russian Foreign Minister Sergei Lavrov told reporters that the talks had focused on implementing a 2018 ceasefire agreement agreed for Idlib -- the last rebel-held bastion in Syria's civil war.

"There is always room for dialogue. Today there were phone talks between presidents Putin and Erdogan... The conversation was detailed and devoted to the necessity to do everything" to implement agreements on Idlib, said Lavrov. "But we need to begin implementing those aims. For half a year nothing has been done. The Syrian army has... every right to reply to constant violations," he added.

Striking a relatively conciliatory tone but also indicating Turkey had to fulfil its responsibilities, Lavrov said Russia was ready to help improve the security of Turkish troops in Idlib. He said Russia expressed its "condolences" for the deaths while adding "such tragedies" could be averted if Turkey gave accurate coordinates for the location of its troops.

He said that Turkey and Russia were in constant contact over Idlib, with Ankara informing Moscow of the locations of its troops on a daily basis -- with these coordinates then passed to the Syrian regime.

However, on this occasion Turkey had not informed Russia its soldiers were in the area hit by Syrian fire, he said, adding they had been among "terrorists". "As soon as this was clear, we asked the Syrian regime to take a pause in military action and do everything to ensure the evacuation of the wounded and allow the transfer of the killed soldiers back to Turkish territory," he added.