Turkey has been mediating between Moscow and Kyiv since Russia sent its armed forces into Ukraine on Feb. 24. The last talks between representatives of Russia and Ukraine were held in Istanbul in the end of March.

The Kremlin did not immediately reply to a request for further comment after issuing a statement on the phone call.

"An exchange of views on the situation around Ukraine continued, including in the context of coordinating efforts to ensure the safety of navigation in the Black Sea and grain exports to global markets," it said.

The Turkish state-owned Anadolu news agency said Erdogan had told Putin on Monday that it was time to act on a United Nations plan to set up a sea corridor for Ukrainian grain exports through the Black Sea.

Since the start of the conflict, Ukraine, one of the world's biggest grain producers, has been unable to use the seaports had been its main export conduit, and has been able to export only around a third of the grain it would previously have sent abroad.

A lack of Ukrainian grain has helped to drive global food prices to record highs and fuelled concerns about food security.

Grain constitutes nearly a fifth of all Ukraine's exports, according to official data.

NATO member Turkey, which has good ties with both Moscow and Kyiv, has criticised the Russian military campaign but also rejected Western sanctions on Russia.

It has, however, refused to accept commercial shipments from Crimea at Kyiv's request since Russia seized the peninsula from Ukraine in 2014.

The Kremlin also said that Putin and Erdogan had discussed Syria, where both countries have deployed armed forces.

It said they had stressed the importance of trilateral meetings including Iran - also militarily engaged in Syria - under the Astana peace framework.