Following a deal reached last month that allowed the resumption of grain exports from Ukraine's ports, UN Secretary-General Antonio Guterres is expected to meet with Ukrainian President Volodymyr Zelensky and Turkish President Recep Tayyip Erdogan in Lvov on Thursday.

The meeting also comes a day after NATO's Secretary-General Jens Stoltenberg said it was "urgent" for the UN's nuclear watchdog to be allowed to inspect Ukraine's Zaporozhye NPP, where Russia has raised fears of a nuclear accident.

A spokesperson for Guterres said that the UN chief, Zelensky, and his Turkish counterpart Erdogan will tackle the grain deal, in addition to "the need for a political solution to this conflict".

He went on to say that he had "no doubt" that the nuclear power plant issue would be raised.

Zelensky said in his regular nightly address that Guterres had arrived and that the two would "work to get the necessary results for Ukraine."

Guterres is scheduled to visit Odessa on Friday, one of three ports involved in the grain exports agreement reached in July under the auspices of the UN and with the assistance of Ankara.

The UN Chief will then travel to Turkey to visit the Joint Coordination Centre, which is in charge of overseeing the agreement.

21 freighters were authorized to sail under the agreement in the first half of August, carrying more than 563,000 tons of agricultural products, including more than 451,000 tons of corn, as per the UN.

The first wartime shipment of UN food aid for Africa arrived, on Wednesday, in the Bosphorus Strait, carrying 23,000 tons of wheat.

A possible nuclear catastrophe

In his address on Wednesday, Zelensky mentioned the Zaporozhye NPP, claiming that Ukrainian diplomats and scientists were in "constant contact" with the International Atomic Energy Agency (IAEA) about sending a mission to the nuclear facility.

In March, Russian forces took full control of the NPP; the Kherson region and most of the Zaporozhye region in Ukraine are now controlled by Russian military forces and local military-civilian administrations that have been formed there.

Since then, Ukraine has waged several attacks on the plant. On July 20, three Kamikaze drones belonging to the Ukrainian Armed Forces targeted the Zaporozhye NPP. A second attack occurred on August 5, which caused two electricity transmission lines to be cut off.

On August 12, the Ukrainian armed forces struck the city of Enerhodar and the Zaporozhye NPP. The city's thermal power station was also struck by Ukrainian troops. Drone attacks by Ukrainian forces have regularly targeted the facility, leading Russia to request help from the IAEA to address security issues.

Such incidents have triggered fears of a possible nuclear catastrophe and were the subject of an emergency meeting of the UN Security Council last Thursday.