By Aram Roston, Humeyra Pamuk and Michelle Nichols

WASHINGTON (Reuters) -The U.S. State Department informed a number of regional allies in the Middle East of Israel’s looming strike on Iran hours before the attack took place, three sources familiar with the matter said on Friday.

In a diplomatic note sent out Thursday afternoon, the State Department confirmed that the Israeli attack was set to take place late on Thursday. Qatar was among the countries which received the heads up.

Washington was not involved in Israel’s operation and was not providing any support, the note said, adding that President Donald Trump has been very clear on his desire for peace in the region but at the same time has been firm that Tehran cannot be allowed to obtain nuclear weapons.

“We don’t comment on private diplomatic conversations,” a State Department spokesperson said when asked about the notifications sent to allies.

Israel launched a barrage of strikes across Iran on Friday, saying it had attacked nuclear facilities and missile factories and killed military commanders in what could be a prolonged operation to prevent Tehran from building an atomic weapon.

The heads up is the clearest illustration of how Washington has been in the loop about Israel’s plans even as the United States maintains it did not take part in the attack and that this was a “unilateral” action by Israel.

In a phone interview with Reuters on Friday, Trump said he and his team knew everything about Israel’s attack plan and that he had given Tehran fair warning it needed to make a deal on its nuclear program.

(Reporting by Aram Roston, Humeyra Pamuk and Michelle Nichols; Editing by Daniel Wallis)