As Iran retaliates, largest US military base in Middle East hit by ballistic missile, Qatar says

More details are surfacing about the conversations had in the days leading up to the operation in Iran, sources told ABC News.

The president spoke with his envoys Steve Witkoff and Jared Kushner by phone on Thursday, multiple sources said.

During that phone conversation, Witkoff and Kushner told the president that Tehran was not serious about ending or dismantling its nuclear enrichment program, sources said.

The White House declined to comment.

In a phone call Saturday, the president told ABC News that talks between the U.S. and Iran had been going "very well." He added, "But in the end, we didn’t think they were going to get there. And they would’ve had in a fairly short period of time some very fairly big nuclear capacity and we were not going to put up with that.”

The CIA had been tracking Iran's Supreme Leader Ayatollah Khamenei for months, tracking his daily movements, a person familiar with the intelligence told ABC News. When they learned there would be a meeting of top leaders on Saturday with the Supreme Leader, the timing of the attack was moved.

-ABC News' Rachel Scott, Mariam Khan and Shannon Kingston

Iranian state media shared a photo of a meeting of the interim leadership council on Sunday.

The picture shows Iranian President Masoud Pezeshkian, Chief Justice Gholam Hossein Mohseni Ejehi and a Secretary of the Guardian Council, Alireza Arafi, sitting around a table in a room. The Islamic Republic of Iran Broadcasting said this is the second meeting of the interim leadership council.

Based on the Islamic Republic's constitution, the council temporarily takes over the leader's responsibilities until a new leader is chosen by the Assembly of the Experts.

-ABC News' Somayeh Malekian

President Donald Trump on Sunday posted a video acknowledging for the first time on camera the death of three U.S. troops killed during the U.S. operation against Iran over the weekend.

The president said he was sending “our immense love and eternal gratitude to the families of the fallen” before warning that more U.S. troops will “likely” be killed as the operation rages on.

“Earlier today, CENTCOM shared the news that three U.S. military service members have been killed in action. As one nation, we grieve for the true American patriots who have made the ultimate sacrifice for our nation, even as we continue the righteous mission for which they gave their lives, we pray for the full recovery of the wounded and send our immense love and eternal gratitude to the families of the fallen,” Trump said.

“And sadly, there will likely be more before it ends. That's the way it is -- likely be more, but we'll do everything possible. But that won't be the case. But America will avenge their deaths and deliver the most punishing blow to the terrorists who have waged war against, basically, civilization,” Trump added.

Trump started the speech by touting the nine Iranian naval vessels he said were sunk, and said, for the first time on camera, that the Ayatollah was dead. The president also said that “the entire military command is gone” in Iran.

Later in the speech, Trump warned that those who did not surrender would face “certain death.”

-ABC News' Meghan Mistry, Nicholas Kerr, Fritz Farrow and Selina Wang

U.S. lawmakers in the House and Senate will receive classified briefings on Tuesday from Trump administration officials on the military operation in Iran, multiple sources told ABC News.

Senators are scheduled to be briefed at 3:30 p.m. ET on Tuesday. A briefing for House members will follow at around 5 p.m., according to the sources

The briefers from the administration are expected to include Secretary of State Marco Rubio, Joint Chiefs Chairman Gen. Dan Caine, CIA Director John Ratcliffe, and Secretary of Defense Pete Hegseth, according to the sources.

-ABC News' Jay O'Brien and Lauren Peller