IAEA’s team arrives near Zaporizhzhia nuclear plant after months of haggling to gain access to the plant amid fighting.

The mission arrived on Wednesday after the head of the International Atomic Energy Agency (IAEA), Rafael Grossi, had sought access to the plant for months for an unprecedented wartime mission.

World leaders have also demanded that the UN watchdog be allowed to inspect it. The complex has been occupied by Russian forces but run by Ukrainian engineers since the early days of the six-month-old war.

With the convoy of vans and UN-marked SUVs finally arriving in the afternoon in Zaporizhzhia city, still some 120km (75 miles) by road from the plant, Grossi said the “real work” will start on Thursday. He underscored the challenges ahead.

“It’s a mission that seeks to prevent a nuclear accident and to preserve this important — the largest, the biggest — nuclear power plant in Europe,” he said.

He said an initial tour will take a few days, after which “we will have a pretty good idea of what’s going on”. Grossi said he had received “explicit guarantees” from Russia that the 14 experts would be able to do their work.

Grossi also said he is hoping the IAEA will be able to establish a “continued presence” at the plant to safeguard it against an accident.

The team’s work on the site, he added, will include a physical inspection of the place, the functioning of the safety system and interviews with the nuclear plant’s staff.

Mikhail Ulyanov, Russia’s representative to the international organisation in Vienna, welcomed the idea that the UN agency’s experts could stay at the site on a permanent basis.

The world watched the mission’s progress with anxiety. European Union foreign policy chief Josep Borrell renewed a call to Russia to fully demilitarise the area around the plant.

“They are playing games. They are gambling with the nuclear security,” Borrell said. “We cannot play war games in the neighbourhood of a site like this.”

While the inspectors were on their way, Russia-backed local authorities accused Ukrainian forces of repeatedly shelling the plant grounds and city where it is situated, Enerhodar. They said drone attacks hit the plant’s administrative building and training centre.

Yevhen Yevtushenko, head of the administration in the Ukrainian-held city of Nikopol, across the Dnieper River from the plant, charged that the attacks were carried out by the Russians in a bid to make Ukraine look like the culprit.

Fighting for Kherson

Meanwhile, fighting continues on the ground, with Ukrainian officials saying they have had “successes” in three areas of the Russian-occupied region of Kherson, two days after Kyiv announced the start of a southern counteroffensive to retake territory.

Yuriy Sobolevskyi, the deputy head of Kherson’s regional council, told Ukraine’s national news broadcaster that Ukrainian troops had had successes in the Kherson, Berislav and Kakhovka districts but declined to give details.

Al Jazeera’s Teresa Bo said that it is worth noting that the front line has been very stable for the past weeks.

“None of these [Russian and Ukrainian] forces have been able to make any major accomplishments, so we’re going to have to see whether Ukraine has enough weapons and manpower to be able to liberate many of those cities that have been occupied by Russia,” she said.

Russia’s defence ministry disputed Ukraine’s claim of successes in the south, stressing that Ukrainian forces have rather suffered heavy losses in equipment and men.

In its daily briefing, Russia’s defence ministry said its forces had shot down three Ukrainian helicopters and that Ukraine had lost four fighter jets during two days of fighting around the Mykolaiv-Kryvyi Rih front line and in other areas of southern Ukraine.

The Reuters news agency and Al Jazeera were unable to verify the battlefield reports.