The Pentagon on Monday rushed to play down reports that U.S. troops in Iraq were being repositioned in preparation for a possible withdrawal, one day after Iraqi lawmakers passed a nonbinding resolution calling for all foreign troops to leave the country.

“This is a mistake,” the chairman of the Joint Chiefs of Staff, Gen. Mark A. Milley, told reporters at the Pentagon after a letter indicating a withdrawal was released to Iraqi officials by the U.S. military command in Baghdad. The letter, he said, was an unsigned planning draft discussing new deployments and “should not have been released.”

“There has been no decision made to leave Iraq, period,” Defense Secretary Mark T. Esper said.

But the quickly quelled uproar was indicative of what Milley called the “highly dynamic situation” in which the United States finds itself after Friday’s killing of Iranian Maj. Gen. Qasem Soleimani in a U.S. drone strike at the Baghdad airport.

A policy afterthought for the past three years, while it served as a hub for military efforts against the Islamic State and a place from which to keep a close eye on Iran, Iraq has suddenly become a problem for the United States.

After bringing the Islamic State to heel and claiming to be well on his way to stopping the “endless wars” in the Middle East, President Trump finds himself in the middle of an entirely new crisis on the same battlefield that bedeviled his two immediate predecessors.

There is widespread agreement among U.S. lawmakers and close allies that Soleimani, commander of the elite Quds Force of Iran’s Islamic Revolutionary Guard Corps, was responsible for years of terrorist activities by Iran, including attacks that have caused the deaths of hundreds of U.S. forces in the region.

Britain, France and Germany on Monday issued a statement urging the United States and Iran to exercise restraint and avoid escalation. Saudi Arabia, whose deputy defense minister met with Secretary of State Mike Pompeo on Monday, issued a similar call.

“We are very keen that the situation in the region doesn’t escalate any further,” Saudi Foreign Minister Faisal bin Farhan al-Saud told reporters in Riyadh. “We hope that all actors take all the steps necessary to prevent any further escalation and any provocation.”

But many worry that the administration has no strategy to deal with the likely escalation of U.S.-Iranian conflict that will follow. That concern is most acute in Iraq, where the two powers have long vied for influence.

“This administration doesn’t have a policy on Iraq,” said a former senior Iraqi official who spoke on the condition of anonymity to avoid worsening a volatile situation. Iraq, he said, has been a subsidiary of policies toward Israel and Iran, seen as “baggage from the last administration.”

Former president Barack Obama came to office determined to end U.S. military involvement in Iraq, withdrawing all combat forces at the end of 2011. But his administration remained deeply involved in political diplomacy there and efforts to stabilize a democratic government. When the Islamic State burst onto the scene in 2014, Obama agreed to an Iraqi request to send U.S. troops, a deployment that Trump said he planned to end as soon as the militants were vanquished.

“Up to the point where ISIS was territorially defeated” last year, a current Iraqi official said, “Iraq was on the radar screen because defeating the Islamic State was an electoral priority of the president. Once they were defeated, we were downgraded.”

Many Iraqis were taken aback early last year when Trump, in an interview with CBS’s “Face the Nation,” indicated that the United States “had Iraq” and intended to keep it for its own purposes. “We spent a fortune on building this incredible base,” Trump said of the al-Asad Air Base in western Iraq, which hosts many U.S. troops. “We might as well keep it.”

“And one of the reasons I want to keep it is because I want . . . to be able to watch Iran. All I want to do is to be able to watch. We have an unbelievable and expensive base built in Iraq. It’s perfectly situated for looking at all over, different parts of the troubled Middle East, rather than pulling up.”

On Sunday, Trump noted that the base “cost billions of dollars” and said that “we’re not leaving unless they pay us back.”

Iraq has been seen largely “through the lens of counterterrorism, through the lens of Iran, and through the lens of the partisan debate of the last decade,” said William Wechsler, a senior Pentagon official under Obama, “none of which is about the sovereignty and future of Iraq, which is what its people care about.”

Within minutes of Sunday’s vote in Baghdad — pushed by pro-Iranian Shiite representatives in a session boycotted by Sunni and Kurdish lawmakers — Pompeo had dismissed it as the flailing of an unrepresentative parliament headed by a lame-duck prime minister.

Any attempt by Iraq to follow through with the expulsion of U.S. troops, Trump later threatened, would be met with a refusal to leave and sanctions on Iraq “like they’ve never seen before, ever.”

Senior State Department officials who briefed reporters late last week insisted that “Iraqis want us in the country” — an argument Esper echoed in comments at the Pentagon on Monday. But there are fears that events of the past few weeks have given pro-Iranian forces an upper hand and distracted attention from anti-Iranian uprisings that have swept Iraq in recent months.

“Iraqis still view both the United States and Iran as malign forces in their country that are interfering in their country’s affairs, pursuing their own agendas without caring about Iraqi sovereignty,” said Ali Fathollah-Nejad of the Brookings Doha Center.

But “at this particular point in time,” he said, the Shiite-dominated “Iraqi political class is using and abusing the situation in order to divert attention from the protests . . . and fanning the flames of anti-Americanism.”

For the U.S. military, the concerns are more immediate. Already, the United States has suspended counter-Islamic State operations in Iraq and Syria while the 5,000 U.S. troops in Iraq turn their attention to force protection in expectation of an Iranian response. NATO and U.S. training of Iraqi troops has also been suspended, and the U.S. government has told American civilians in Iraq to leave the country.

Current and former officials said a prolonged pause in counterterrorism operations, let alone a U.S. departure, would hurt American security interests in the region.

“Force protection is our #1 priority. Period,” Lt. Gen Pat White, who heads the international mission against the militants in Iraq and Syria, said in a message on Twitter. Beyond Iraq, U.S. troops across the region remained on heightened alert Monday.

Officials are particularly concerned about the potential for Iranian attacks within the next few days, now that the mourning period for Soleimani has ended. “We are seriously concerned about the next 24 to 48 hours,” said a U.S. official who was not authorized to address the issue publicly.

The administration has dispatched more than 4,000 additional troops to the region. An additional amphibious force of about 4,500 sailors and Marines is also scheduled to arrive in the region to support Middle East operations.

The order was disclosed as throngs of Iranians mourned Soleimani at his funeral Monday in Tehran. Ayatollah Ali Khamenei, Iran’s supreme leader, wept as he prayed over the general’s coffin, and he and other Iranian leaders vowed revenge.

Beyond the immediate threat, U.S. officials said it would be difficult if not impossible to continue the mission targeting the Islamic State in Syria, where there are 1,000 U.S. troops, without a presence in Iraq.

Former officials and analysts said the Trump administration might seek to mitigate Iraq’s decision to reduce the American presence, requesting “dual key” status, which would require Iraqi approval for all U.S. military operations or moving U.S. troops to the semiautonomous Kurdistan region.

At the Pentagon on Monday, Milley said he had followed up on reports of the withdrawal letter, which he said referred not to troops leaving Iraq but to movements inside Iraq and to new forces being deployed, saying it “should not have been released.”

“The first part of it, which says ‘repositioning forces over the course of the coming days to prepare for onward movement’ was poorly worded, [and] implies withdrawal. That is not what’s happening,” he said.

Esper said the United States remains prepared for any contingency with regard to Iran, and the message to Tehran is that the “ball remains in their court.”

The United States encourages Iran to de-escalate the situation, he said, adding that “we are open to sitting down with them and discussing the issues, so we could have a more normal relationship with that country.”

Asked whether the U.S. military would strike cultural sites in Iran, as Trump has suggested, Esper said, “We will follow the laws of armed conflict.”