President Trump served a bellicose brew of threats, rebukes and contempt on Sunday as he escalated tensions in the Middle East and awaited Iran’s possible retaliation for the U.S. killing of one of its top generals.

Trump projected a wartime posture as he wrapped up his holiday vacation here, reiterating that if Iran took military action against the United States he may order attacks on Iranian cultural sites, which could constitute a war crime under international law. He vowed on Twitter to “quickly & fully strike back, & perhaps in a disproportionate manner.”

Trump threatened Iraq as well. He countered the Iraqi parliament’s move Sunday to try to expel foreign troops, including U.S. forces, by telling reporters that he would respond by imposing “very big sanctions” on the nation and demanding that Iraq reimburse the United States for the billions of dollars it had invested in a major air base there.

Should Iraq force out the Americans, Trump said, “We will charge them sanctions like they’ve never seen before, ever. It’ll make Iranian sanctions look somewhat tame.”

He added that he would impose “very big sanctions” on Iraq “if there’s any hostility, that they do anything we think is inappropriate.”

Trump also flouted protocols at home, making a mockery of his necessity to advise Congress of military action by writing on Twitter that his tweets would serve as official notification of strikes.

As leaders in capitals around the world monitor the fallout from last week’s U.S. drone strike that killed Iranian Maj. Gen. Qasem Soleimani, Trump let loose in all directions without regard to law or convention or even policy. He was characteristically pugnacious, appearing to be acting on the theory that bold, even belligerent threats would compel the Iranians to cower or relent.

“The United States just spent Two Trillion Dollars on Military Equipment. We are the biggest and by far the BEST in the World! If Iran attacks an American Base, or any American, we will be sending some of that brand new beautiful equipment their way … and without hesitation!” the president wrote in a tweet posted just past midnight from Mar-a-Lago, Trump’s seaside club in Palm Beach, where he celebrated Christmas and New Year’s.

But Trump’s rhetoric alarmed congressional leaders who worry that he has been making erratic decisions devoid of grand strategy and without wise counsel. The president’s vow to target Iranian sites of historic and cultural significance prompted particular concern.

On Twitter late Saturday, Trump said that the United States was targeting 52 Iranian sites, representing the 52 American hostages taken by Iran four decades ago, and that some of those are “a very high level & important to Iran & the Iranian culture.”

The 1954 Hague Convention for the Protection of Cultural Property bans the targeting of cultural sites with military action; there is a provision that allows for a waiver due to “military necessity.”

Iran has 24 locations on the U.N. list of cultural world heritage sites.

Secretary of State Mike Pompeo, who appeared across the Sunday public affairs shows, struggled to explain Trump’s warning. He did not directly state whether cultural centers in Iran would be considered fair targets, but insisted that any U.S. action would be legal.

“We’re going to do the things that are right and the things that are consistent with American lives,” Pompeo, a graduate of the U.S. Military Academy, said on CNN’s “State of the Union.” “If the Iranian leadership makes a bad decision, we hope that they won’t. But when they do, America will respond.”

In a separate interview on CBS’s “Face the Nation,” Pompeo said Trump’s reference to the 52 potential target sites in Iran was “entirely consistent” with the administration’s message of de-escalation.

“Iranian leadership needs to understand that attacking Americans is not cost-free,” Pompeo said during that interview. “Setting out conditions that say these are our expectations, these are the things that America is expecting from you and if you don’t do them, the cost will be clear and direct.”

A few hours later, however, Trump contradicted Pompeo by doubling down on his threat of striking cultural sites.

“They’re allowed to kill our people,” he told reporters aboard Air Force One during his flight home to Washington. “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 site? It doesn’t work that way.”

Trump’s tough talk is emblematic of a president who has flouted the tenets of international and U.S. law on war crimes. He has insisted that enhanced interrogation tactics such as waterboarding work, suggested killing terrorists’ families to fight the Islamic State and two months ago cleared three members of the U.S. armed services accused or convicted of war crimes over objections from senior military officials.

Trump’s threat drew fierce rebukes from Democratic lawmakers and former national security officials, as well as some Republicans, who noted that targeting cultural sites with military action violates international law.

“Targeting civilians and cultural sites is what terrorists do. It’s a war crime. Trump is stumbling into a war of choice,” tweeted Sen. Chris Murphy (D-Conn.), a member of the Foreign Relations Committee. “A war entirely of his making. A war that will get thousands of Americans killed. Congress must stop him.”

Sen. Brian Schatz (D-Hawaii) tweeted in response to Trump’s Air Force One comments: “What an awful, awful example around the world and within our country.”

Rep. Will Hurd (R-Tex.) said Sunday night on MSNBC’s “Kasie DC”: “We shouldn’t be attacking cultural sites and I don’t see our military planners suggesting or identifying sites to hit. … Going after cultural sites is not something that I would advise or I think should happen.”

Former U.S. national security officials said the Pentagon would not target cultural property because it would violate domestic and international laws.

“It would be a war crime. DOD has very professional planners who take their obligations and fidelity to law seriously,” said Kelly Magsamen, a former official at the National Security Council and the Pentagon who is now at the Center for American Progress, a liberal think tank. “Any military planner, any U.S. soldier would know that. The fact that the president of the United States doesn’t know that is profoundly frightening to me. If he does know it and he’s still saying it, that’s even worse.”

Trump has endorsed lethal actions defined as war crimes by international and U.S. laws and widely condemned as crimes against humanity.

As a candidate and in his first months in office, Trump said enhanced interrogation methods, such as waterboarding, are an effective tactic to elicit information — practices at odds with the Geneva Conventions, the U.N. Convention Against Torture and the U.S. Detainee Treatment Act of 2005.

“I happen to feel that it does work,” the president said in January 2017, referring to “torture or waterboarding or however you want to define it — enhanced interrogation I guess would be a word.”

Trump also said during a December 2015 appearance on “Fox and Friends” that one way to win the fight against the Islamic State is to “take out their families.”

“They care about their lives, don’t kid yourself,” he said. “When they say they don’t care about their lives, you have to take out their families.”

More recently, Trump overruled military leaders and cleared three members of the armed forces who had been accused or convicted of war crimes. In November, Trump ordered full pardons to former Army 1st Lt. Clint Lorance, who was serving a 19-year sentence for the murder of two civilians, and Maj. Mathew L. Golsteyn, a former Special Forces officer who was facing murder charges for killing an Afghan detainee suspected of being a Taliban bombmaker.

The president also ordered the Navy to restore Chief Petty Officer Edward Gallagher to his previous rank. Gallagher had been acquitted of murder and convicted of posing with the corpse of an Islamic State fighter in Iraq.

The killing of Soleimani has also sparked a new debate within the Democratic presidential field about how to characterize the death of the Iranian military leader. Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.) have termed the killing an “assassination” — a word that others in the race have avoided or even criticized more-liberal candidates for using.

“Donald Trump has ordered the killing of a government official of Iran, a high military leader in Iran, and in doing so has escalated an attack on Iran, and increased the likelihood that we will end up in another war in the Middle East,” Warren said Saturday while campaigning in Manchester, Iowa.

Speaking Sunday on CNN, former South Bend, Ind., Mayor Pete Buttigieg said he was “not interested in the terminology, I’m interested in the consequences” when asked about the use of the word. But in North Carolina on Friday, former New York mayor Mike Bloomberg called the phrase “outrageous” as it related to Soleimani, noting that the Iranian leader was someone “who had an awful lot of blood on his hands.”

Rucker reported from Washington. Dave Weigel in Manchester, Iowa, contributed to this report.