Iranian Foreign Minister Abbas Araghchi warned on Saturday that any U.S. involvement in ongoing Israeli attacks on Iran would prove “very, very dangerous.”

 The warning came after U.S. President Donald Trump gave Tehran a two-week deadline to reach a diplomatic deal over Iran’s nuclear program, or risk American military strikes on Iranian nuclear sites.

Israel’s military, meanwhile, said on Saturday that it struck an Iranian nuclear research facility overnight and killed three senior Iranian commanders in targeted attacks.

“The U.S. has been involved in the aggression since day one,” said Araghchi, speaking in Istanbul, which is hosting a meeting of the Organization of Islamic Cooperation (OIC).

The conference was convened after Israeli air attacks on Iranian military facilities, aiming at dismantling its nuclear program, escalated into a full-blown ballistic exchange that has lasted nine days now. Trump has lent his support to Israel, but has so far not decided whether to intervene militarily on the side of the American ally.

Araghchi added that Tehran is “absolutely ready for a negotiated solution for our nuclear program.”

Turkey’s President Recep Tayyip Erdoğan also commented on the ongoing conflict, calling Israeli Prime Minister Benjamin Netanyahu the “biggest obstacle to regional peace.”

“Netanyahu’s Zionist ambitions have no other purpose than to drag our region and … the whole world into a big disaster,” Erdoğan said at the conference.

The target of Israel’s overnight attack was two centrifuge production sites, and the attacks came on top of strikes on other centrifuge production sites elsewhere in recent days, the Associated Press reported, citing an Israeli military official. It was the second attack on Isfahan, which was hit in the first 24 hours of the war as part of Israel’s goal to destroy the Iranian nuclear program, the AP said.

Meanwhile, the Israel Defense Force claimed it killed Saeed Izadi, a commander in Iran’s Revolutionary Guards Corps responsible for dealing with Palestinian militants. The IDF said Izadi had been eliminated in the city of Qom following a “prolonged intelligence-gathering effort.”