No breakthroughs appear to have come out of Thursday’s meeting among Ukrainian President Volodymyr Zelenskyy, U.N. Secretary-General António Guterres and Turkish President Recep Tayyip Erdogan, as the conflict with Russia approaches the six-month mark with no end in sight.

There was some hope their summit in the western Ukraine city of Lviv would yield progress on issues related to the war, though not major steps that would lead to the conflict’s end. Even lesser agreements would require the assent of Vladimir Putin, who did not participate. Erdogan, who has tried to serve as a mediator in the dispute, said he will consult with the Russian president.

The three participants Thursday discussed expanding exchanges of prisoners of war and arranging for U.N. atomic energy experts to visit and help secure Europe’s biggest nuclear power plant in Zaporizhzhia, which is in the middle of fierce fighting that has raised fears of catastrophe.

“The area needs to be demilitarized, and we must tell it as it is: Any potential damage in Zaporizhzhia is suicide,” Guterres said.

Meanwhile, Russian missile strikes that began Wednesday night continued Thursday morning in and around the northeastern city of Kharkiv, killing at least 17 and wounding 42, Ukrainian authorities said. Zelenskyy called the assault “despicable and cynical.”

Latest developments:

In the latest in a series of incidents on Russian soil near the border with Ukraine, an ammunition dump caught fire in the Belgorod region, the regional governor said. No casualties were reported.

Amid the tense international climate created by the war, Russia deployed warplanes carrying state-of-the-art hypersonic missiles to its Kaliningrad region, which is surrounded by two NATO countries, Poland and Lithuania.

Mariupol’s minister of education and four school principals are suspected of treason, the Prosecutor General’s Office of Ukraine said. They’re accused of cooperating with Russian occupation authorities in Mariupol and heading “a pseudo-organization that organizes the educational process in the city,” the office said.