WASHINGTON (AP) — President Donald Trump insisted Sunday that Iranian cultural sites were fair game for the U.S. military, dismissing concerns within his own administration that doing so could constitute a war crime under international law. He also warned Iraq that he would levy punishing sanctions if it expelled American troops in retaliation for a U.S. airstrike in Baghdad that killed a top Iranian official.

Trump’s comments came amid escalating tensions in the Middle East following the killing of Gen. Qassem Soleimani, the head of Iran’s elite Quds force. Iran has vowed to retaliate and Iraq’s parliament responded by voting Sunday to oust U.S. troops based in the country.

Trump first raised the prospect of targeting Iranian cultural sites Saturday in a tweet. Speaking with reporters Sunday as he returned to Washington from his holiday stay in Florida, he doubled down, despite international prohibitions.

“They’re allowed to kill our people. They’re allowed to torture and maim our people. They’re allowed to use roadside bombs and blow up our people. And we’re not allowed to touch their cultural sites? It doesn’t work that way,” Trump said.

The targeted killing of Soleimani sparked outrage in the Middle East, including in Iraq, where more than 5,000 American troops are still on the ground 17 years after the U.S. invasion. Iraq’s parliament voted Sunday in favor of a nonbinding resolution calling for the expulsion of the American forces.

Trump said the U.S. wouldn’t leave without being paid for its military investments in Iraq over the years — then said if the troops do have to withdraw, he would hit Baghdad with economic penalties.

“We will charge them sanctions like they’ve never seen before ever. It’ll make Iranian sanctions look somewhat tame,” he said. “If there’s any hostility, that they do anything we think is inappropriate, we are going to put sanctions on Iraq, very big sanctions on Iraq.”

He added: “We’re not leaving until they pay us back for it.”

The administration has scrambled to contend with the backlash to the killing of Soleimani. Though he was responsible for the deaths of hundreds of Americans, the targeted American strike marked a stark escalation in tensions between Washington and Tehran.

Secretary of State Mike Pompeo said the U.S. military may well strike more Iranian leaders if the Islamic Republic retaliates. He tip-toed around questions about Trump’s threat to attack Iranian cultural sites, a military action that likely would be illegal under the laws of armed conflict and the U.N. charter.

Pompeo said only that any U.S. military strikes inside Iran would be legal.

“We’ll behave inside the system,” Pompeo said. “We always have and we always will.”

Trump’s warnings rattled some administration officials. One U.S. national security official said the president had caught many in the administration off guard and prompted internal calls for others in the government, including Pompeo, to clarify the matter. The official, who was not authorized to speak publicly to the issue, said clarification was necessary to affirm that the U.S. military would not intentionally commit war crimes.

Oona Hathaway, an international law professor at Yale and a former national security law official in the Defense Department’s legal office, said Trump’s threat amounted to “a pretty clear promise of commission of a war crime.”

The president’s threats to Iran did little to quell Tehran’s furor over the death of Soleimani. Iranian state television reported that the country would no longer abide by any limits of the 2015 nuclear deal it signed with the United States and other world powers. Trump withdrew the U.S. from the deal in 2018 and stepped up economic sanctions on Tehran — actions that accelerated a cycle of hostilities leading to the last week’s killing.

The administration also pushed back Sunday on questions about the legality of the strike on Soleimani. Pompeo said the administration would have been “culpably negligent” in its duty to protect the United States if it had not killed him. He did not provide evidence for his previous claims that Soleimani was plotting imminent attacks on Americans. Instead of arguing that an attack had been imminent, he said it was inevitable.

“We watched him continue to actively build out for what was going to be a significant attack – that’s what we believed – and we made the right decision,” he said, adding later: “We continue to prepare for whatever it is the Iranian regime may put in front of us within the next 10 minutes, within the next 10 days, and within the next 10 weeks.”

Congressional Democrats were skeptical.

“I really worry that the actions the president took will get us into what he calls another endless war in the Middle East. He promised we wouldn’t have that,” said Chuck Schumer of New York, the Senate’s top Democrat.

Schumer said Trump lacks the authority to engage militarily with Iran and Congress needs a new war powers resolution “to be a check on this president.” To which Pompeo said: “We have all the authority we need to do what we’ve done to date.”

Sen. Mark Warner, D-Va., said the administration violated the Constitution by not consulting with Congress in advance.

“It’s also important because one, you potentially get members of Congress to buy in ahead of time, and two, they may ask that hard question that’s not asked in an insular group,” Warner said.

Congressional staffs got their first briefings from the administration on Friday, and members were expected to be briefed this week.

But Trump made clear Sunday that he saw little reason to give Congress advanced warning if he orders the military to carry out further actions against Iran.

“These Media Posts will serve as notification to the United States Congress that should Iran strike any U.S. person or target, the United States will quickly & fully strike back, & perhaps in a disproportionate manner,” he wrote on Twitter. “Such legal notice is not required, but is given nevertheless!”

Democrats in Congress have complained that Trump’s order to kill Soleimani took place without first consulting with or informing top lawmakers, noting that Congress still holds sole power to declare war. Trump did meet the 48-hour deadline required by the War Powers Act to notify Congress of the deadly drone strike, though the document provided Saturday was entirely classified and no public version was released.

Moving swiftly to rebuke Trump for not consulting with Congress, House Speaker Nancy Pelosi said late Sunday the House would introduce and vote this week on a war powers resolution to limit the president’s military actions regarding Iran. In a letter to House Democrats, Pelosi called the airstrike “provocative and disproportionate” and that it had “endangered our servicemembers, diplomats and others by risking a serious escalation of tensions with Iran.” A similar resolution was introduced in the Senate.

Some of the Democrats running to challenge Trump in November questioned whether he had a long-term plan for the Mideast.

Former Vice President Joe Biden said Trump was ill-prepared for the repercussions of the strike on Soleimani and had alienated allies by not alerting them of the plans. “I think we need a president who could provide steady leadership on Day One,” he said. “The next president is going to inherit a divided nation and a world in disarray.”

Pete Buttigieg, the former mayor of South Bend, Indiana. said: “When you’re dealing with the Middle East, you need to think about the next and the next and the next move. This is not checkers. And I’m not sure any of us really believe that this president and the people around him’’ are “really going through all of the consequences of what could happen next.”

Pompeo appeared on ABC’s “This Week,” CNN’s “State of the Union,” NBC’s “Meet the Press,”’ CBS’ “Face the Nation,’’ ”Fox News Sunday” and Fox News Channel’s “Sunday Morning Futures.” Schumer was on ABC, Warner and Warren were on NBC, Petraeus was on CBS, Buttigieg was on CNN and Graham was on Fox News Channel.