Ukrainian President Volodymyr Zelensky and his French counterpart Emmanuel Macron spoke Sunday, discussing the “functioning” of a sea corridor set up by Kyiv for safe navigation of ships after Moscow exited a landmark grain deal.

The phone call came on the eve of a summit in Russia between President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan, who wants to revive the grain deal, and as Moscow hit Ukraine’s Odesa region with drones.

“We also discussed ways to ensure the functioning of the grain corridor and enhance the security of the Odesa region,” Zelensky said on social media after a phone call with Macron.

Ukraine this week said four more ships had gone through its temporary maritime corridor in the Black Sea, which it had set up last month to ensure safe navigation.

Erdogan is due to meet Putin in Russia’s Black Sea resort of Sochi on Monday, amid hopes for the revival of the deal.

Zelensky also thanked Macron for France’s “crucial military aid” to Kyiv and said the pair “discussed the next packages.”