

But the IRGC statement also seemed to offer an opening: implying that if the U.S. does not respond to the strike, the escalation can end. That could prove a tough call for Trump, who has issued a range of threats against Iran in recent days and often acts unpredictably, but who has also defused tensions with Tehran before.

In his tweet saying Iran wasn’t seeking escalation or war, Zarif, the Iranian foreign minister, further described the Iranian strike as measured. “Iran took & concluded proportionate measures in self-defense under Article 51 of UN Charter targeting base from which cowardly armed attack against our citizens & senior officials were launched,” he wrote.

The Pentagon said Iran launched more than a dozen missiles, and that it was clear the missiles were fired directly from Iran. That in itself is notable, as Iran often targets the U.S. through proxy militias beyond its borders. That it chose a direct response signals the depth of anger in Tehran over Soleimani’s killing.

According to the Pentagon, the missiles “targeted at least two Iraqi military bases hosting U.S. military and coalition personnel at Al-Assad and Irbil,” both areas in Iraq. The Pentagon added that the bases “have been on high alert due to indications that the Iranian regime planned to attack our forces and interests in the region.”

Iraqi Prime Minister Adel Abdul-Mahdi said in a statement Wednesday that Iran notified his government of the attack shortly after midnight, when officials in Tehran said they would only strike locations with a U.S. military presence, according to the Associated Press. Abdul-Mahdi said he was simultaneously informed of the assault on the military bases by the U.S. government.

“Iraq refuses any violation of its sovereignty and any attacks on its territory,” the prime minister said, adding that Iraq was seeking to avoid a “devastating all-out war.”

On Capitol Hill, Speaker Nancy Pelosi (D-Calif.) was handed a note about the attack while she was speaking at a House Democratic Caucus meeting in the basement of the Capitol, according to lawmakers inside the room. She then left the room and later took a call from Vice President Mike Pence, who briefed her on the attack, Pelosi spokesman Drew Hammill said.

Democratic lawmakers emerging from the closed-door meeting were visibly shaken. Rep. Barbara Lee (D-Calif.), a longtime antiwar advocate, said the situation was “spiraling.”

House Minority Leader Kevin McCarthy’s office said the president had called the California Republican to brief him on the Iranian attack.

One leading Republican hawk, Rep. Liz Cheney of Wyoming, said the U.S. should retaliate.

“The Iranians have been warned. They were warned,” Cheney, who chairs the House Republican Conference, said in a brief interview. “What looks to have been a direct attack on American facilities from Iranian territory is a significant escalation, and the president has been very clear that an attack on our bases will be taken seriously. And there ought to be a retaliation.”

On Fox News on Tuesday night, Iran hawks, including host Sean Hannity, appeared to speak directly to the president to nudge him to stay strong in the face of Iran’s escalation.

Hannity opened up his show by saying that Iran was "going to get hit hard" and warned that the country’s three major oil refineries could soon go up in flames. His guests then echoed that doom-and-gloom message, with Sens. Lindsey Graham and Ted Cruz speaking about potential retaliation and the threat Iran would pose if it ever obtained nuclear weapons.

"This was an act of war, Sean, by any reasonable definition,” Graham said. “The missiles were launched from Iran at targets inside of Iraq housing military. The president has all the authority he needs under Article II to respond. How he responds is yet to be determined.”

He then added that he wanted to deliver a message to Iran directly: "Your fate is in your own hands in terms of the regime's economic viability. You continue this crap, you're going to wake up one day out of the oil business."

Other lawmakers faulted Trump, blaming him for an “impulsive” decision last week to take out Soleimani. That decision was made after an Iranian-backed militia group in Iraq staged an attack that killed an American contractor, crossing a line that Trump had warned Iran not to.

“I fear we’re far from the end of it,” Rep. Tom Malinowski (D-N.J.), a former senior State Department official, said.

“No one can defend Iran taking a single shot at an American military installation,” Malinowski added. “We have to be able to defend ourselves and to deter further attacks. But at the same time, it’s fair to ask, even more so today, whether an apparently impulsive decision that the president took made us more or less safe.”

Retired U.S. Army Lt. Gen. Mick Bednarek, the former chief of the Office of Security Cooperation in Iraq, said he worried the situation would now spin out of control.

“The broader, strategic situation of all this is awful,” he said. “While many of our diplomats are urging restraint, that is simply not Trump’s persona. I am very concerned about where all this is leading.“

That said, Trump has backed down against Iran before. This past summer, as the two countries feuded over what the U.S. alleged were Iranian attacks on international oil tankers, the president called off a U.S. military strike against Iran after Tehran downed an American drone, saying he'd decided it wasn’t worth the potential cost in lives.

All House members are expected to receive a top-secret briefing Wednesday afternoon on the escalating situation with Iran. The briefing was scheduled before the Iranian attacks. Secretary of State Mike Pompeo, Defense Secretary Mark Esper and CIA Director Gina Haspel are among the officials expected to brief lawmakers. Pompeo and Esper went to the White House on Tuesday after the Iranian strike.

On Tuesday, meanwhile, acting Secretary of Homeland Security Chad Wolf and other officials with that agency were briefing House and Senate committees on the overall Iran threat landscape. Those briefings, too, were apparently scheduled before the Iranian strike.

A DHS official who confirmed the briefings said there was no specific, credible threat to the homeland, but that the department was operating at an enhanced posture.

The IRGC statement said it was calling its operation “Martyr Soleimani.” The missiles were launched amid ongoing mourning for the dead general in Iran. In recent days, Iranians across the country have marched in his memory.