The last ship to travel under a U.N.-brokered deal that allows the safe Black Sea export of Ukrainian grain left the port of Odesa early on Sunday ahead of a deadline to extend the agreement, according to a Reuters witness and MarineTraffic.com.

Russia has not agreed to register any new ships since June 27 and the initiative will expire on Monday unless Moscow agrees to extend it.

A United Nations spokesman said on Friday that Secretary-General Antonio Guterres was waiting for a response from Russian President Vladimir Putin on a proposal to extend the deal.

Putin told South African President Cyril Ramaphosa in a phone call on Saturday that commitments to remove obstacles to Russian food and fertiliser exports had yet to be fulfilled, the Kremlin said.

Russia has repeatedly threatened to quit the deal, brokered by the U.N. and Turkey in July 2022 following Russia's invasion of Ukraine. It had been previously extended for two months on May 17.

Ukrainian officials did not immediately comment on whether the ship, the Turkish-flagged TQ Samsun, had left Odesa.

Ukraine and Russia are among the world's top grain exporters.

(Reporting by Iryna Nazarchuk and Dan Peleschuk; editing by Barbara Lewis)