Russian President Vladimir Putin and his Turkish counterpart Tayyip Erdogan agreed in a telephone call on Sunday for Istanbul to host the talks, which Ankara hopes will lead to a ceasefire in Ukraine.
Mr Erdogan said Mr Putin and Ukraine president Volodymyr Zelenskyy are “valuable friends” as he set the scene for talks.
He claimed progress made in Istanbul could pave the way for the leaders to meet – adding that Turkey could host that too.
The Russian and Ukrainian teams were told both sides have “legitimate concerns” but Mr Erdogan insisted today’s talks need to yield “concrete results”.
The talks are being held in Istanbul
MURAT CETINMUHURDAR/PPO
The two sides are hoping to negotiate a peace deal
MURAT CETINMUHURDAR/PPO
Mr Erdogan said: "At such a critical time we are pleased to welcome you and to contribute to your efforts to establish peace.
"I wish that our meetings and discussions will prove to be auspicious for your countries, our region and all humankind."
He has called for an immediate ceasefire and says stopping the tragedy of the current war is up to both sides.
Turkey is a NATO member but retains strong ties with Russia.
Mr Erdogan has resisted joining the West’s sanctions against Moscow, making Turkey one of the few countries yet to do so.
It comes as Foreign Secretary Liz Truss has accused Mr Putin of using the "abhorrent tactic" of abducting Ukrainian civilians.
In a tweet, Ms Truss said he was "resorting to desperate measures".
Her comments came after a Ukrainian human rights group, Zmina, said it had identified dozens of people who had been taken captive.
The group also claims that "thousands" of Ukrainians have been taken to Russia against their will.