The agreement expires on July 17 unless Russia agrees to extend it -- something it has indicated strongly it will not do.

Erdogan used his good working relations with both Russian President Vladimir Putin and Ukrainian leader Volodymyr Zelensky to help seal the UN-backed deal last July.

The agreement helped relieve spiking food prices that were contributing to hunger across parts of Africa and other drought and conflict-riven lands.

"Mr. Zelensky favours continuing the initiative, and Mr. Putin has some suggestions," Erdogan told reporters at the end of a two-day NATO summit in the Lithuanian capital Vilnius.

"We are working on a solution by taking these suggestions into account."

The deal has allowed Ukraine to export more than 32 million tonnes of grain and foodstuffs from three Black Sea ports.

Ukrainian officials said that Russian attack drones had targeted grain facilities at one of the ports this week.

Moscow is unhappy about the operation of a parallel agreement on free exports of Russian food and fertiliser.

Russia has also argued that most of the grain being exported from Ukraine was reaching rich nations instead of the world's poor.

Official data compiled by the United Nations shows just 2.5 percent of the grain and foodstuffs being exported to low-income countries under the so-called Black Sea Grain Initiative.

Ukraine was one of the world's top grain producers before Russia invaded in February 2022.