KYIV, Ukraine — A team of international nuclear experts made its way toward an imperiled nuclear plant in Ukraine on Wednesday morning from Kyiv, the capital, heading south toward the front lines where fighting has intensified in recent weeks.
The group includes 14 experts with the International Atomic Energy Agency, the United Nations nuclear watchdog. They set off from Kyiv on Wednesday morning after a news conference outlining one of the most complicated missions in the agency’s history. The I.A.E.A. has also worked in Iraq, Iran and North Korea.
A senior Ukrainian official warned that many challenges remained as the group made its way to the plant. One of the biggest obstacles will be finding safe passage through an active battlefield to the Russian-occupied facility.
To reach the Zaporizhzhia nuclear power plant, the team must negotiate the craters and trenches of the front lines and enter an area where frequent shelling has raised fears of a nuclear catastrophe. The team could reach the front line between Russian and Ukrainian forces as early as Wednesday afternoon.
“As you know, we have a very, very important task there to perform, to assess the real situation there, to help stabilize the situation as much as we can,” the I.A.E.A. director general, Rafael Grossi, told reporters in Kyiv early Wednesday before departing in a convoy of armored S.U.V. vehicles.
Monitors intended to spend several days in the Russian-occupied nuclear facility, and will seek to establish a permanent monitoring mission at the plant, Mr. Grossi said. “After six months of steady efforts, the I.A.E.A. is moving in to the Zaporizhzhia nuclear power plant,” he said.
The Russian-appointed head of the Zaporizhzhia region, Yevhen Balytskyi, contradicted Mr. Grossi and said the visit was expected to last only one day, calling the delegation’s stated goal for the visit vague.
“They have one day to inspect the operation of the plant,” he said, adding, “If they say some elements need to be attended to, we’ll be able to do so.”
Before the experts set out for the nuclear plant, Europe’s largest, they tried to broker some kind of deal with the two militaries. Fighting is intensifying in the south, where Ukraine is escalating strikes in what could be part of broader counteroffensive.
By early Wednesday, Mr. Grossi said the mission had secured safety guarantees from both the Russian and Ukrainian militaries, though dangers lingered. “We are going to a war zone,” he said, “we are going to occupied territory.”
Both Russia, whose forces seized the plant not long after invading, and Ukraine, whose military holds positions only a few miles away, say they support the I.A.E.A. mission. But they have disagreed on how it should be carried out. Russian officials have ignored pleas to withdraw from the facility to create a demilitarized zone around it.
Mykhailo Podolyak, an adviser to Ukraine’s president, said in an interview on Tuesday that key aspects of the negotiations were in question, among them the route to the facility. He said he was still hopeful, however, that the monitors would reach the plant “one way or another.”