UNITED NATIONS (AP) — Russia and Ukraine on Monday traded blame before the United Nations Security Council for the attacks on Europe’s largest nuclear power plant, which the head of the International Atomic Energy Agency said have put the world “dangerously close to a nuclear accident.”

Without attributing blame, IAEA Director General Rafael Mariano Grossi said his agency has been able to confirm three attacks against the Zaporizhzhia Nuclear Power Plant since April 7.

“These reckless attacks must cease immediately,” he told the Security Council. “Though, fortunately, they have not led to a radiological incident this time, they significantly increase the risk … where nuclear safety is already compromised.”

The remote-controlled nature of the drones that have attacked the plant means that it is impossible to definitively determine who launched them, Grossi told reporters after the meeting.