Ukrainian President Volodymyr Zelensky, his Turkish counterpart Recep Tayyip Erdogan and UN chief Antonio Guterres will meet in Ukraine on Thursday, the United Nations announced.
Guterres will then on Friday visit the Ukrainian port city of Odessa -- one of three ports being used in the recent deal to export grain from the war-ravaged country -- before heading to Turkey.
The first UN-chartered vessel laden with grain left Ukraine on Tuesday for Africa following the hallmark deal brokered by Turkey and the UN to relieve the global food crisis.
The vessel departed from the Ukrainian port of Pivdennyi and will sail to Djibouti for delivery to Ethiopia, Ukraine's infrastructure ministry said.
Ukraine has said it is hoping two or three similar shipments will follow soon.
Ukraine and Russia, two of the world's biggest grain exporters, agreed on a deal brokered by the UN and Turkey last month to unblock Black Sea grain deliveries after Russia's invasion.
"At the invitation of President Volodymyr Zelensky, the secretary-general will be in Lviv on Thursday to attend a trilateral meeting with President Recep Tayyip Erdogan of Turkey and the Ukrainian leader," Guterres's spokesman Stephane Dujarric said at a press briefing Tuesday in New York.
"The secretary-general will then go on to Odessa the next day where he will visit the port which is one of the three being used as part of the Black Sea grain initiative."
At talks, the leaders will discuss "the need for a political solution to this conflict," Dujarric said, adding "I have no doubt that the issue of the nuclear power plant" will be raised.
Kyiv and Moscow have traded accusations over a series of strikes this month on the Zaporizhzhia nuclear plant in southern Ukraine -- Europe's largest.