DNIPRO, Ukraine (AP) — The head of the U.N.’s atomic energy watchdog crossed the front line in the war in Ukraine to visit Europe’s largest nuclear power plant Wednesday, and warned that it was easy to see evidence of intensified fighting in the area that poses a threat to the facility’s safety.

The increasing combat makes it urgent to find a way to prevent a potentially catastrophic nuclear accident at the Zaporizhzhia Nuclear Power Plant, said Rafael Mariano Grossi, director general of the International Atomic Energy Agency.

“It is obvious that this area is facing perhaps a more dangerous phase,” he said of the facility, which is in a partially Russian-occupied part of Ukraine. “We have to step up our efforts to get to some agreement of the protection of the plant.”

Grossi has struggled to agree with Russian and Ukrainian authorities on a deal to secure the plant, which has been hit several times during the Ukraine war. The site has also suffered several losses of external power needed to cool its six shut-down reactors, forcing it to rely on emergency back-up generators. 

Wednesday’s visit to the plant was Grossi’s second since the start of the war. He tried for months to negotiate on securing the whole zone around the complex, but he said at a news conference during his visit that the concept “is evolving” to focus more on protecting the plant itself.

Grossi said he was working on “realistic measures” and had narrowed the scope in the hopes of reaching agreement on a mutually acceptable plan.

“Initially we were focusing on the possibility of the establishment of a well determined zone around the plant,” he told reporters during his visit. “Now the concept is evolving. It’s refocusing more on the protection itself, and the things that should be avoided, for example, in order to protect the plant, rather than on territorial aspects, which pose certain problems.”

The IAEA, based in Vienna, Austria, has been rotating inspection teams at the power plant since Grossi’s visit in September. Grossi told The Associated Press in an interview Tuesday that it is his duty to ramp up talks between Kyiv and Moscow aimed at safeguarding the facility and avoiding a catastrophic accident. He said a deal was “close.”

Grossi met Monday with Ukrainian President Volodymyr Zelenskyy and said he would “most probably” head to Moscow in the coming days. 

However, Zelenskyy said in a separate interview with AP that he was less optimistic a deal was near. “I don’t feel it today,” he said.

Speaking in the central Ukrainian city of Dnipro after his visit, Grossi said he saw clear signs of increased military activity in the area and assessed damage the plant sustained in shelling last November, which he described as “quite severe.”

Buildings near two of the reactors were hit “wittingly or unwittingly, … so this is very serious,” he said, adding that his visit allowed him to confirm “the gravity … of the situation and the need for us to get to results as soon as possible.”

He didn’t give details of the evolving security plan, but said that “not using the plant as a military platform is very important” as stationing heavy military equipment there can become a target.

Equally, he said, there should be “of course no attacks, no targeting. And we saw that at least until November, there were attacks. So I hope there won’t be another one. But the reality and the facts prove that there have been.”

The Kremlin’s forces took over the plant after Russia’s full-scale invasion of Ukraine in February 2022. Zelenskyy opposes any proposal that would legitimize Russia’s control.

Interruptions to the outside electricity supply due to the fighting required plant personnel to switch to emergency diesel generators six times during the 13-month war. When backup power supplies might be needed again is unpredictable, Grossi told AP. ___

Follow AP’s coverage of the war in Ukraine at https://apnews.com/hub/russia-ukraine