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.

Turkey said the talks could begin as early as Monday, but Kremlin spokesperson Dmitry Peskov said that was unlikely as the negotiators would only be arriving in Turkey on Monday. Peskov added that no major progress had been made in the talks themselves, or on the idea of a potential meeting between Putin and Ukrainian President Volodymyr Zelenskiy.

In separate comments, Russian Foreign Minister Sergei Lavrov said a meeting between the two leaders would be counterproductive if it were held now. He said they should meet once the sides achieve progress.

Ukrainian President Volodymyr Zelenskiy said in a video address to the Ukrainian people late on Sunday that in the Istanbul talks his government would prioritise the "territorial integrity" of Ukraine and any agreement must be guaranteed by third parties and put to a referendum.