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

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

The Israel Defense Forces released a statement early Monday morning saying projectiles had been launched from Lebanon toward several areas of northern Israel.

"Sirens sounded in several areas in northern Israel following projectiles launched from Lebanon. The details are under review," the IDF said.

The IDF later said that the projectiles were intercepted and that no damage or injuries occurred.

-ABC News' Will Gretsky

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