Western leaders reportedly pressured the UN nuclear watchdog to publish an accusatory report on Tehran ahead of Israeli airstrikes

European leaders "bear a share of the blame" for Israel's attack on the Islamic Republic, as they pressured the International Atomic Energy Agency (IAEA) to give Iran a negative assessment ahead of the airstrikes, Russian Foreign Minister Sergey Lavrov has said.

Washington announced a tentative ceasefire in the Israel-Iran conflict on Tuesday, just days after the US military joined the Jewish state's air campaign in striking Tehran's nuclear sites. Israel attacked Iran shortly after the UN nuclear watchdog declared Tehran to be in breach of the Non-Proliferation Treaty (NPT). Iran has stressed that its nuclear program is peaceful and accused the IAEA of abandoning impartiality.

European leaders pressured the organization's director, General Rafael Grossi, into publishing an accusatory report on Iran, Lavrov said in a speech in Moscow on Tuesday.

"The Europeans have taken a purely neocolonial position... They were actively preparing Grossi so that he would put the most ambiguously negative formulations into his report," the top diplomat said.

The UK, France, Germany, and later, the US ran with the IAEA assessment and pushed a resolution through the IAEA Board of Governors that condemned Iran for allegedly violating the NPT, he added.

READ MORE: UN official gave Israel cover - and Iran paid the price

"A few days later, Israel launched its attacks," Lavrov said.

This highlights that the West "exerts very serious influence on international organizations, and has even privatized them to an extent," Lavrov said, adding that most such bodies are no longer "guided by the requirement of impartiality."

Weeks before the escalation, Reuters cited anonymous diplomats as saying that Western powers were pressuring the IAEA to declare Tehran in breach of its NPT obligations, at the height of US-Iran nuclear talks.

Tehran has since accused Grossi of taking sides and turning a blind eye to Israel's attacks on Iran's nuclear energy facilities. Multiple IAEA resolutions state that any use of force against peaceful nuclear facilities is illegal under international law.

Moscow has condemned Israeli and US attacks against Iran as "illegitimate." The recent ceasefire, announced by US President Donald Trump on Tuesday, "can and should be welcomed," Kremlin spokesman Dmitry Peskov has said. Moscow hopes that it "proves to be sustainable," he added.