Turkey wants a possible deal on resuming Ukrainian grain exports from the Black Sea under a United Nations-led plan to be put in writing this week after a general agreement was reached last week, President Recep Tayyip Erdoğan said Wednesday.

On Monday, Ankara said a second meeting between Russia, Ukraine, Turkey and the U.N. would "probably" be held this week.

Erdoğan told reporters after meeting his Russian counterpart Vladimir Putin on the sidelines of a summit in Iran that he remained hopeful about an agreement.

"An agreement emerged from the talks in Istanbul last week on the general outline of the process under the U.N. plan. Now, we want to tie this agreement to a written document," Erdoğan said on a return flight from Tehran.

"We hope the plan will begin to be implemented in the coming days," he added.

He also said Turkey and Russia, maritime neighbors in the Black Sea, would continue their solidarity on natural gas and the Akkuyu nuclear power plant, adding he had also discussed the procurement of amphibious airplanes from Russia with Putin.

Erdoğan has tried to use his good relations with Putin and Kyiv’s leader Volodymyr Zelenskyy to find a solution and continue negotiations about Ukraine.

Russia’s invasion of Ukraine – two major global wheat suppliers – has sent prices for grains and other food products soaring. It has stalled Kyiv’s exports, leaving dozens of ships stranded and some 22 million tons of grain stuck in silos at Ukrainian ports.

Moscow has denied responsibility for worsening the food crisis, instead blamed Western sanctions' chilling effect for slowing its food and fertilizer exports and Ukraine for mining its Black Sea ports.

Ukraine and Russia are major global wheat suppliers, and the latter is also a large fertilizer exporter, while former is a significant producer of corn and sunflower oil.

Putin on Tuesday said "progress" had been made in discussions towards exporting grain from Ukraine. Yet, he said any deal hinged on the West’s willingness to yield some ground.

"We will facilitate the export of Ukrainian grain, but we are proceeding from the fact that all restrictions related to possible deliveries for the export of Russian grain will be lifted," he said.

Putin personally thanked Erdoğan for playing a central mediation role in the dispute.