KYIV, Aug 26 - Russia late Friday blocked agreement on the final document of a four-week review of the U.N. treaty considered the cornerstone of nuclear disarmament which criticized its military takeover of Europe’s largest nuclear plant soon after Russian troops invaded Ukraine, an act that has raised fears of a nuclear disaster.

Igor Vishnevetsky, deputy director of the Russian Foreign Ministry’s Non-Proliferation and Arms Control Department, told the delayed final meeting of the conference reviewing the 50-year-old Nuclear Nonproliferation Treaty that “unfortunately there is no consensus on this document,” The Associated Press reported.

The final document needed approval of all countries at the conference that are parties to the treaty aimed at curbing the spread of nuclear weapons and ultimately achieving a world without them.

Ukraine accused Russia of continued attacks in the area close to the Zaporizhzhia Nuclear Power Plant over the weekend with the Ukraine’s Energoatom issuing a map forecasting the not only Ukrainian territory may suffer from the radiation leak, but also Russia’s.

Attacks were also reported over the weekend in the cities of Nikopol and Marhanets, each about 10 kilometers from the facility.

The U.N.’s International Atomic Energy Agency also reported Sunday that radiation levels were normal, that two of the Zaporizhzhia plant’s six reactors were operating and that while no complete assessment had yet been made, recent fighting had damaged a water pipeline, since repaired.

The radiation map Ukraine’s Energoatom issued showed that based on wind forecasts for Monday, a nuclear cloud could spread across southern Ukraine and southwestern Russia. Release of the map may have been meant to warn that if Russian forces were responsible for a radiation leak, their own country would suffer. In the 1986 Chernobyl nuclear power plant accident, the world’s worst atomic energy catastrophe, radiation spread from Ukraine to several neighboring countries.

Authorities last week began distributing iodine tablets to residents who live near the Zaporizhzhia plant in case of radiation exposure. Much of the concern centers on the cooling systems for the plant’s nuclear reactors. The systems require electricity, and the plant was temporarily knocked offline Thursday because of what officials said was fire damage to a transmission line. A cooling system failure could cause a nuclear meltdown.

Periodic shelling has damaged the power station’s infrastructure, Energoatom, said Saturday.

“There are risks of hydrogen leakage and sputtering of radioactive substances, and the fire hazard is high,” it said.

The IAEA has tried to work out an agreement with Ukrainian and Russian authorities to send a team to inspect and secure the plant, but it remained unclear when the visit might take place.

Heavy fighting also continued in strategically significant Ukrainian cities of Kramatorsk and Sloviansk in the Donetsk region, with no casualties reported, said Pavlo Kyrylenko, the Donetsk region’s governor.

The Nuclear Nonproliferation Treaty review conference is supposed to be held every five years but was delayed because of the COVID-19 pandemic. This marked the second failure of its 191 state parties to produce an outcome document.

The issue that changed the dynamics of the conference was Russia’s invasion of Ukraine on Feb. 24, which brought Russian President Vladimir Putin’s warning that Russia is a “potent” nuclear power and that any attempt to interfere would lead to “consequences you have never seen.” He also put Russia’s nuclear forces on high alert.

Putin has since rolled back, saying that “a nuclear war cannot be won and must never be fought,” a message reiterated by a senior Russian official on the opening day of the NPT conference on Aug. 2.

The occupation of the Zaporizhzhia nuclear plant in southeastern Ukraine as well as the takeover of the Chernobyl nuclear plant, scene of the world’s worst nuclear disaster in 1986, renewed global fears of another nuclear emergency.

The four references in the draft final document to the Zaporizhzhia plant, where Russia and Ukraine accuse each other of shelling, would have had the parties to the NPT express “grave concern for the military activities” at or near the facility and other nuclear plants. (ap/ez)