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

The Gang of 8 and key leaders of national security committees are expected to receive a classified briefing on Iran from Trump administration officials on Monday, multiple sources told ABC News.

Members of the Gang of 8 include the top bipartisan House and Senate leaders and the chairs and ranking members of the House and Senate intelligence committees.

As ABC News previously reported, the House and Senate will receive a classified briefing from the administration on Tuesday.

-ABC News' Jay O’Brien, Lauren Peller and Allison Pecorin

The Israel Defense Forces announced further strikes against Iran in the early hours of Monday.

The IDF said the Israeli Air Force has launched another wave of strikes toward "targets of the Iranian Terror Regime in the heart of Tehran."

-ABC News' Will Gretsky

Oil is trading at $72.39 a barrel, up 8% since the attacks in Iran took place.

This comes as Rystad Energy says that traffic in the Strait of Hormuz is at a virtual standstill.

Dow futures are down about 500 points as of Sunday night.

The most important question for oil markets is what happens in the Strait of Hormuz, one of the world’s most important chokepoints for oil. Roughly 20% of the world’s oil passes through the Strait, according to the U.S. Energy Information Administration.

According to the EIA, the strait is deep enough and wide enough to handle the world's largest crude oil tankers. Saudi Arabia and the UAE have some infrastructure in place that can bypass the Strait of Hormuz, which may mitigate any transit disruptions through the strait.

British Prime Minister Keir Starmer said Sunday that he would allow the United States to use U.K. bases at Diego Garcia in the Indian Ocean and the RAF Fairford base in England for strikes against Iran.

The decision comes a week after Starmer denied a formal request from the U.S. to use the bases.

Starmer said the change was because of Iran’s indiscriminate targeting of civilians in Middle East countries, which he said has put British citizens at risk.

"Iran is striking British interests nonetheless, and putting British people at huge risk, along with our allies across the region. That is the situation we face today," the prime minister said in a video statement posted to social media.

He said that British military personnel were nearly struck by a missile that landed close to the U.S. Navy base in Bahrain.

"Our Armed Forces, who are located across the region, are also being put at risk by Iran’s actions. Yesterday Iran hit a military base in Bahrain, narrowly missing British personnel," Starmer said.

-ABC News' Luis Martinez