Turkish President Recep Tayyip Erdogan said he would follow up with his Russian counterpart Vladimir Putin, given that most of the matters discussed would require the Kremlin's agreement.With the meetings held at such a high level — it was the first visit to Ukraine by Erdogan since the war broke out and the second by Guterres — some had hoped for breakthroughs, if not toward an overall peace, then at least on specific issues. But none was apparent.

Meeting in the western city of Lviv, far from the front lines, the leaders discussed such things as expanding exchanges of prisoners of war and arranging for UN atomic energy experts to visit and help secure Europe's biggest nuclear power plant, which is in the middle of fierce fighting that has raised fears of a catastrophe.

Erdogan has positioned himself as a go-between in an effort to stop the fighting. While Turkey is a member of NATO, its wobbly economy is reliant on Russia for trade, and it has tried to steer a middle course between the two combatants.

On the broader topic of peace efforts, the Turkish president urged the international community after the talks not to abandon diplomatic efforts to end the war that has killed tens of thousands and forced more than 10 million Ukrainians from their homes.

He repeated that Turkey is willing to act as a "mediator and facilitator" and added, "I remain convinced that the war will end at the negotiating table."

In March, Turkey hosted talks in Istanbul between Russian and Ukrainian negotiators, but the effort to end the hostilities failed.

One major topic at the talks in Lviv was the Zaporizhzhia nuclear plant in southern Ukraine. Moscow and Kyiv have accused each other of shelling the complex.

Accusing Moscow of "nuclear blackmail," Zelensky has demanded that Russian troops leave the plant and that a team from the UN's International Atomic Energy Agency be allowed in.

"The area needs to be demilitarized, and we must tell it as it is: Any potential damage in Zaporizhzhia is suicide," Guterres said at a news conference.

Zelenskyy and the UN chief agreed Thursday on arrangements for an IAEA mission to the plant, according to the president's website.

But it was not immediately clear whether the Kremlin would consent to the proposed terms. As for a pullout of troops, a Russian Foreign Ministry official said earlier that that would leave the plant "vulnerable."

Concerns about the plant mounted Thursday when Russian and Ukrainian authorities accused each other of plotting to attack the site and then blame the other side.

Guterres used the talks in Lviv to name General Carlos dos Santos Cruz of Brazil to lead a previously announced UN fact-finding mission to the Olenivka prison, where 53 Ukrainian prisoners of war were killed in an explosion in July. Russia and Ukraine have blamed each another for the blast.

An increase in grain exports was also on the agenda on Thursday. Earlier this summer, the UN and Turkey helped broker an agreement clearing the way for Ukraine to export 22 million tonnes of corn and other grain stuck in its Black Sea ports since the Russian invasion.

The blockage has worsened world food shortages, driven up prices and heightened fears of famine, especially in Africa. Yet even with the deal, only a trickle of Ukrainian grain has made it out — some 600,000 tons by Turkey's estimate.

Zelenskyy said Thursday that he had proposed expanding the shipments. Guterres, for his part, touted the operation's success but added, "There is a long way to go before this will be translated into the daily life of people at their local bakery and in their markets."