71 killed in Israeli attack on Iran prison, official says

Since the State Department began assisting departure flights for American nationals from Israel on Saturday, there have been a total of seven flights that have left the country, a State Department official told ABC News.

Approximately 250 U.S. citizens and lawful permanent residents, and their accompanying immediate family members, were aboard the flights, the official said.

The flights have arrived in Athens, Greece; Rome, Italy; and Larnaca, Cyprus.

-ABC News' Shannon Kingston

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