Turkish President Tayyip Erdogan discussed the Black Sea grain export agreement on Sunday with the leaders of Russia and Ukraine, as both sides seek changes that would boost their exports.
Turkey has acted as mediator alongside the United Nations in the grain deal, which opened up Ukrainian ports for exports after a six-month de facto Russian blockade.
Moscow is seeking better guarantees for its own food and fertilizer exports, while Kyiv wants the deal expanded to increase the number of Ukrainian ports it opens for shipping.
After his call with Putin, the Turkish presidency said Erdogan had called for a quick end to the conflict and said Moscow could start work on exporting more food products and commodities through the Black Sea grain corridor.
Russia has urged the United Nations to push the West to lift some sanctions, to ensure Moscow can freely export its fertilizer and agricultural products - a part of the Black Sea grain deal that Moscow says has not been implemented.
"The deal is of complex character, which requires the removal of obstacles for the relevant supplies from Russia in order to meet the demands of the countries most in need," the Kremlin said in a statement.
Talks with Ukraine
Zelensky said on Twitter he had "discussed further work & possible expansion of the grain corridor" with Erdogan.
Ukraine and Russia are both among the world's largest grain producers and exporters. Russia's blockade of Ukrainian ports following its invasion threatened to cause a global food crisis earlier this year, which was mitigated by the Turkish-brokered deal that unblocked Ukrainian shipments at the end of July.
The Kremlin said Erdogan and Putin also discussed a Russian proposal to create a base in Turkey for exports of Russian natural gas.
Putin suggested the idea in October as a means to redirect supplies from Russia's Nord Stream pipelines to Europe, damaged in explosions in September. Erdogan has supported the concept.
"The special importance of joint energy projects, primarily in the gas industry, was emphasized," the Kremlin said.
Gazprom chief Alexei Miller held talks with Erdogan in Istanbul in the past week.