Ukrainian President Volodymyr Zelenskiy will hold talks with his Turkish counterpart Tayyip Erdogan in Istanbul on Saturday, amid tensions between Kyiv and Moscow over a long-running conflict in Ukraine's eastern Donbass region.
Kyiv has raised the alarm over a buildup of Russian forces near the border between Ukraine and Russia, and over a rise in violence along the line of contact separating Ukrainian troops and Russia-backed separatists in Donbass.
The Russian military movements have fuelled concerns that Moscow is preparing to send forces into Ukraine. The Kremlin denies its troops are a threat, but says they will remain as long as it sees fit.
Zelenskiy and Erdogan are scheduled to hold bilateral talks at 1230 GMT, chair a cooperation meeting, and hold a joint news conference. Erdogan's office said all aspects of Turkey-Ukraine ties and steps to deepen cooperation would be discussed.
"Regional and international issues will be on the agenda of the talks as well, on the basis of the understanding that peace and stability be preserved," it said in a statement.
The United States says Russia has amassed more troops on Ukraine's eastern border than at any time since 2014, when it annexed Crimea from Ukraine and backed separatists in Donbass.
On Friday, Turkey said Washington will send two warships to the Black Sea next week.
NATO member Turkey has forged close cooperation with Russia over conflicts in Syria, Libya and Nagorno-Karabakh, as well as in the defence and energy areas. But it has criticised Crimea's annexation and supported Ukraine's territorial integrity. It has also sold drones to Kyiv in 2019.
Ukraine and Russia have traded blame for the increase in violence in the conflict, which Kyiv says has killed 14,000 people since 2014.
Russian President Vladimir Putin, in a call with Erdogan on Friday, accused Ukraine of "dangerous provocative actions" in Donbass.
Kyiv said on Saturday Ukraine could be provoked by Russian aggravation of the situation in Donbass.
"We want the problems between the two countries to be solved in a peaceful manner, through dialogue," Turkish Defence Minister Hulusi Akar said on Wednesday. "We are trying to keep balance with Russia and other Black Sea coastal countries without causing a crisis," he added.