The UN secretary general, António Guterres, has called for a demilitarised zone around the Zaporizhzhia nuclear plant, involving the withdrawal of Russian occupying troops and the agreement of Ukrainian forces not to move in. Guterres was addressing a UN security council session on Tuesday, at which he supported the recommendations put forward Rafael Mariano Grossi, the director general of the International Atomic Energy Agency (IAEA) who led an inspection visit to the occupied Zaporizhzhia plant last week, and presented a report to the security council. The report confirmed the presence of Russian soldiers and military equipment at the plant, including army vehicles. “We are playing with fire and something very, very catastrophic could take place. This is why in our report, we are proposing the establishment of a nuclear safety and security protection zone limited to the perimeter and the plant itself,” Grossi said. Guterres said that, as a first step, Russian and Ukrainian forces should cease all military operations around the plant. “As a second step, an agreement on a demilitarised perimeter should be secured,” he added. “Specifically, that will include the commitment by Russian forces to withdraw military personnel and equipment from that perimeter and the commitment by Ukrainian forces not to move in.” The Russian ambassador to the UN, Vasily Nebenzya, blamed recent shelling of the plant on Ukraine and portrayed Russian forces as protecting the plant. He did not respond to the call for a security zone, a proposal Moscow has so far rejected. Nebenzya said he had not had time to read the IAEA report. Sergiy Kyslytsya, Ukraine’s ambassador, said that Kyiv would have to look at the details of the IAEA’s recommendations, but offered qualified support for the proposal of a demilitarised zone if it involved full Russian withdrawal. The IAEA report presented on Tuesday said the agency was “gravely concerned” about the “unprecedented” situation at the plant, which is controlled by Russian forces but operated by Ukrainian technicians, and urged interim measures to prevent a nuclear disaster. The report came as Russian state media confirmed that the Russian colonel who served as the military commandant of the occupied Ukrainian city of Berdiansk was killed by a car bomb attack, in the most significant assassination yet of an official working for occupying forces. The car bomb reportedly exploded near the city administration, which is being used as a Russian headquarters. Photographs showed that the car used by the Russian military official, who has been identified as Col Artyom Bardin, was severely damaged in the attack, which took place close to midday. Russian officials have alleged that Ukrainewas behind the attack. If true, it would be the most significant assassination yet of an official working for the occupational government of Russia in Ukraine. Ukrainian staff were operating under constant high stress and pressure, especially with the limited staff available, the report said. “This is not sustainable and could lead to increased human error with implications for nuclear safety,” it added. Britain’s ambassador to the UN, Dame Barbara Woodward, told the security council the Zaporizhzhia staff were “no longer workers, but hostages being held at gunpoint.” Russian troops seized control of the site in early March and there have been repeated attacks in the vicinity, prompting fears of a nuclear disaster. Moscow and Kyiv have denied responsibility and the report did not ascribe blame for the damage its inspectors had discovered. The UN agency sent a 14-person team to the site last week, including its director general, Rafael Grossi, to assess the situation at the plant. At least two members of the team are to remain there on a permanent basis to ensure the facility’s safety. “There is an urgent need for interim measures to prevent a nuclear accident arising from physical damage caused by military means,” the IAEA said. “This can be achieved by the immediate establishment of a nuclear safety and security protection zone. “The IAEA recommends that shelling on site and in its vicinity should be stopped immediately to avoid any further damages to the plant and associated facilities.” The IAEA said that, during its inspection, its team “closely witnessed shelling in the vicinity of the power plant, in particular on 3 September when the team was instructed to evacuate to the ground level of the administrative building”. On the same day, the plant was disconnected from its last remaining main power line to the grid and was relying on a reserve line. “While the ongoing shelling has not yet triggered a nuclear emergency, it continues to represent a constant threat to nuclear safety and security with potential impact on critical safety functions that may lead to radiological consequences with great safety significance,” the inspectors wrote. Areas damaged by shelling included a turbine lubrication oil tank and the roofs of various buildings such as one housing a spent fuel transporter vehicle. Grossi is expected to brief the UN security council in New York on his findings later on Tuesday. Also on Tuesday, a Russian colonel who served as the military commandant of the occupied Ukrainian city of Berdiansk was killed in a car bombing, Russian state media confirmed. At least two Ukrainians collaborating with the Russian government were killed in suspected partisan attacks in August. In one case, the deputy head of the Russian-installed military administration was shot to death in his home in the city of Nova Kakhovka. In late August, a Ukrainian politician from Volodymyr Zelenskiy’s party who had gone over to work with the Russians was killed in the Kherson region. Earlier, blasts rang out and power was cut in Enerhodar, the city surrounding the plant, according to Dmytro Orlov, the Ukrainian mayor who operates from outside Russian-held territory. Moscow repeated its longstanding accusations that Ukrainian forces had been shelling the plant. Kyiv says it is Russia that has been staging such incidents, to undermine international support for Ukraine and as a possible pretext to cut the plant from the Ukrainian power grid and steal its output. On the battleground in the east of the country on Tuesday, three civilians were killed in Russian rocket attacks in the Kharkiv region, a senior official said. In the past week the focus of fighting has shifted to the south, where Ukraine has started a long-awaited counterattack to recapture territory seized early in the war. Ukrainian officials posted an image online of three soldiers raising Ukraine’s flag on a rooftop in Vysokopyllya, in the north of Kherson. If confirmed, it could mark perhaps the most strategic breakthrough on the battlefield in the counteroffensive.