The Russian and Ukrainian delegations arrived in Turkey's largest city Istanbul on Monday for a fresh round of face-to-face peace talks, aiming to achieve substantial progress to end the crisis.

The Russian delegation has settled in the Ciragan Palace Kempinski hotel while the Ukrainian delegation has checked in the Shangri-La Bosphorus, both very close to each other in the Besiktas district.

Media reports said the arrival of the Ukrainian delegation had been postponed to evening hours due to the closure of Ukrainian airspace and some logistical problems. According to the NTV broadcaster, the Ukrainian delegates had to go to a neighboring country by road to fly to Istanbul.

Tuesday's negotiations will begin at 10:30 a.m. local time (0730 GMT) at the Dolmabahce Presidential Working Office in Besiktas.

Turkish President Recep Tayyip Erdogan is expected to address the delegations at the opening of the meeting.

"We will have a short meeting with the delegations tomorrow morning," Erdogan said at a press conference after a cabinet meeting in the Turkish capital Ankara on Monday.

So far, Russia and Ukraine have held three rounds of in-person talks in Belarus, and their fourth session was in a video conference format.

Turkey, meanwhile, has increasingly accelerated its diplomatic efforts in the international arena, reiterating its policy that it is ready to play a mediator role for lasting peace in the region.

In a phone call on Sunday, Erdogan told his Russian counterpart, Vladimir Putin, that a ceasefire and peace between Moscow and Kiev must be achieved as soon as possible, and the humanitarian situation in the region should be improved.

Erdogan repeated that Turkey would continue to contribute in every possible way during this process.

The "phone traffic" that he has been conducting with Putin and Ukrainian President Volodymyr Zelensky is progressing in a positive direction, Erdogan said on Monday.

Turkey has been exerting significant efforts to resolve the crisis through agreement and dialogue, he said.

Produced by Xinhua Global Service