Turkish President Recep Tayyip Erdogan has discussed Ukrainian grain exports in separate phone calls with Russian President Vladimir Putin and Ukrainian President Volodymyr Zelenskiy.
Ukraine and its allies have pushed for the reopening of Ukraine's Black Sea ports, which Kyiv says are shut because of a Russian blockade.
Western countries have increased their demands for the reopening of the ports to allow shipments of grain, especially to countries in the Middle East and Africa that depend on Ukrainian grain to feed their populations.
Erdogan told Putin that it is time to take action regarding a UN plan to establish safe corridors in the Black Sea for grain exports. He also reiterated that a lasting and just peace should be negotiated to end the war, according to a statement from the government communications office quoted by the state news agency Anadolu.
Zelenskiy said on Twitter that he appreciated Erdogan's help on resuming grain exports and added that Russia also must be stopped from taking Ukrainian grain from occupied territories.
Erdogan, who has offered to mediate on the grain issue, also discussed the situation with Putin.
The Kremlin said that the two leaders also discussed economic cooperation and a planned "Russian-Turkish meeting at the highest level" in the near future. No further details were provided.
The Ukrainian Navy, meanwhile, said it had begun helping to facilitate the export of Ukrainian agricultural products. The navy said in a statement that eight foreign ships had arrived at Ukrainian ports.
It said the assistance was possible because Ukraine managed to retake Snake Island, a strategic outpost in the Black Sea. The statement, which was posted on Facebook, also notes that currently most Ukrainian ports remain blocked, and some are occupied.
Moscow said it would allow Ukrainian ships loaded with food products to leave if Ukraine's military demined the waters off Odesa and other ports.
But Ukraine says it cannot demine the coast because Russia would "use grain corridors to attack southern Ukraine."
The war and the blockade of Ukrainian ports have meant most of Ukraine's grain is not getting out, causing food shortages in some of the world's poorest countries. Russia and Ukraine jointly account for nearly a third of global wheat exports.
Many Western countries blame Moscow for food insecurity around the world, but Russia has repeatedly denied it is responsible for the problem.