Military activity is increasing near the Zaporizhzhia nuclear plant in Ukraine, the head of the UN's nuclear watchdog has said.
Rafael Grossi went behind Russian lines on Wednesday for his second visit to the plant since the invasion.
He said he was seeking a deal between Moscow and Kyiv in which both would commit not to attack the plant.
The two sides have blamed each other for shelling nearby that has raised fears of a nuclear disaster.
The International Atomic Energy Agency recently said the world was fortunate to have escaped a catastrophe in the first year of the war.
Mr Grossi, the IAEA's director general, said his calls for a safety zone around the plant had evolved into a possible agreement not to shoot.
“We are focusing on the protection itself … rather than on territorial aspects, which pose certain problems,” he told AFP during a press tour organised by Moscow.
Pro-Kremlin media quoted Mr Grossi as saying the situation “is not improving, and military operations around this territory are intensifying”.
Russia occupies the plant, which is near the front line of fighting, and announced the purported annexation of the wider Zaporizhzhia region last autumn.
The conflict has led to cuts in external power and concern for the well-being of Ukrainian staff at the plant.
But radiation levels have remained normal and there has been no direct damage to Zaporizhzhia's six reactors, the IAEA said last month.
It likewise said there was no cause for concern about radiation levels at the Chernobyl disaster site, which was briefly occupied by Russia last year.
Three other nuclear plants are still in Ukrainian hands but have suffered power cuts because of Russian strikes on the energy grid.