The United Nations and Russian officials on Monday began negotiations on a possible extension of a deal allowing the safe export of grain from Ukraine's Black Sea ports.

Russia's full-scale invasion of Ukraine in February last year saw Ukraine's Black Sea ports blocked by warships until a pact signed in July allowed for the safe passage of exports of critical grain supplies.

The Black Sea Grain Initiative, brokered by Türkiye and the U.N., aimed to prevent a global food crisis by allowing Ukrainian grain to be safely exported from three ports.

The deal was extended for 120 days in November and will renew on March 18 if no party objects.

Moscow has already signaled it will only agree to an extension if restrictions affecting its own exports are lifted, but many diplomats and senior officials, including Turkish Defense Minister Hulusi Akar, are optimistic that the deal will be renewed.

Russian officials say that although the country's agricultural exports have not been explicitly targeted by the West, sanctions on its payments, logistics and insurance industries have created a barrier for its grain and fertilizer exports.

U.N.'s trade and development agency UNCTAD head Rebeca Grynspan and humanitarian chief Martin Griffiths arrived at the U.N. European headquarters in Geneva on Monday morning, without making a comment.

Deputy Foreign Minister Sergei Vershinin is representing Russia at the talks.

The Russian mission in Geneva confirmed to Agence France-Presse (AFP) that the negotiations had started.

Two sources involved with the talks told Reuters they were initially scheduled to last just one day but could be extended as needed.

According to the U.N., more than 24.1 million tons of foodstuff have been exported under the grain deal.

While the Black Sea Grain Initiative concerns the export of Ukrainian grain, the second agreement, between Moscow and the U.N., is aimed at facilitating the export of Russian food and fertilizers, which are exempt from Western sanctions imposed on Moscow.

Last Tuesday, U.N. chief Antonio Guterres said during a visit to Kyiv that it was crucial to extend the deal.

Grynspan was in the Ukrainian capital last Wednesday for talks on the grain initiative.

Türkiye has previously said that it is working hard to extend the deal. "In separate talks with the Russian and Ukrainian sides, we saw that both sides are approaching this positively," Akar said on Sunday. "We are of the opinion that the duration will be extended on March 18," he added.

Nearly half of the exports shipped under the deal are corn, and more than a quarter are wheat, according to U.N. data.

Around 45% of the exports went to developed countries. The biggest recipient was China, followed by Spain, Türkiye, Italy and the Netherlands.