71 killed in Israeli attack on Iran prison, official says

After announcing that Israel and Iran have agreed to a ceasefire, President Donald Trump said it was a "wonderful day for the world" in a phone interview with NBC News.

"It's a great day for America. It's a great day for the Middle East. I'm very happy to have been able to get the job done. A lot of people were dying and it was only going to get worse," Trump said.

Trump said he believes that the 12-day war between Israel and Iran is over.

When asked how long the ceasefire would be, Trump said, "I think the ceasefire is unlimited. It's going to go forever."

-ABC News' Kelsey Walsh

In the first official U.S. military confirmation of the Iranian attack targeting Al-Udeid Airbase in Qatar, U.S. Central Command said the missile barrage was "defeated by U.S. and Qatari Patriot batteries."

CENTCOM also confirmed that there were no casualties to American or Qatari personnel.

"We will continue to aggressively defend our service members and partners in the region. Our adversaries should have no doubt about our resolve or our capabilities," CENTCOM Commander Gen. Michael Erik Kurilla said in a statement.

-ABC News' Luis Martinez

The White House transmitted its official notice of the U.S. strikes on Iran to Congressional Leaders in the House and Senate Monday evening.

Under the War Powers Resolution, the administration has 48 hours after an attack to notify Congress of its action. This notification arrived before the deadline.

The letter, posted to the White House's website, does not appear to provide many new details on the strike.

"I directed this military action consistent with my responsibility to protect United States citizens both at home and abroad as well as in furtherance of United States national security and foreign policy interests," President Donald Trump wrote in the letter. "I acted pursuant to my constitutional authority as Commander in Chief and Chief Executive and pursuant to my constitutional authority to conduct United States foreign relations."

Both the House and the Senate are slated to receive classified briefings on Iran on Tuesday.

-ABC News' Lauren Peller and Allison Pecorin

Vice President JD Vance reacted live to President Donald Trump's social media post announcing a ceasefire between Israel and Iran in an interview with Fox News.

"Tomorrow really is a new day -- the end of the 12-day war, the end of the Iranian nuclear program and I really do believe the beginning of something very big for peace in the Middle East," Vance told Bret Baier.

The vice president said he previewed Trump's social media post before he went on air with Fox News.

"He's been working the phones constantly -- frankly, before the 12-day war started, but certainly over the past 12 days," Vance said. "The president's been extremely clear about America's national objective -- it is to create a world where Iran cannot build a nuclear weapon."

Vance said he thinks Trump has "hit the reset button" and called the conflict "an important reset moment for the entire region."

-ABC News' Kelsey Walsh