A bipratisan group of congressional leaders will take part in the confidential briefing as tensions between the U.S. and Tehran skyrocket | Win McNamee/Getty Images Trump’s Iran rhetoric sparks warning of Iraq war redux Congressional leaders will get more information during a confidential briefing with Trump officials.

WASHINGTON — Lawmakers on both sides of the aisle warned President Donald Trump on Wednesday to avoid plunging the United States into another Iraq-like war in the Middle East, demanding more information about vague warnings that Iran might be planning attacks on U.S. personnel and facilities in the region.

Congressional leaders will get more information about the situation on Thursday during a confidential briefing with Trump officials, according to two Democratic sources. On Capitol Hill and on the campaign trail, politicians fretted the situation feels eerily similar to the run-up to the Iraq war.

"It's close to inconceivable that the president, the administration would consider a war with Iran," said Utah Senator Mitt Romney, a Republican critic of the president. "The president made it clear when he ran for president that one of the worst foreign policy mistakes in American history was the decision to go to war with Iraq. And that we would repeat that [is] unthinkable and something I can't imagine the president or his senior staff would consider."

House Speaker Nancy Pelosi, who will attend Thursday's briefing, minced no words during a closed-door Democratic caucus meeting Wednesday, which came as the State Department evacuated non-emergency staffers from the U.S. Embassy in Baghdad.

"Let me say that we have to avoid any war with Iran," she said, according to a congressional aide.

Pelosi's deputy, Maryland Representative Steny Hoyer, stressed that all members of Congress must get a briefing. "This is a serious situation and we want to make sure we're not getting ahead of ourselves," he said.

Senator Ron Johnson (R-Wis.) said Senate foreign relations Chairman Jim Risch (R-Idaho) is seeking an all-senators briefing for next week.

"I think there's a lot more to be known before decisions are made," said Senator Jerry Moran (R-Kan.).

Tensions between Iran and the United States have spiked in the past week as U.S. officials announced fresh intelligence that Iran or its proxies in the region are planning attacks on American troops, diplomats and facilities.

Democrats challenging Trump for the presidency in 2020 quickly jumped into the fray, comparing the burgeoning situation to the run-up to the U.S. invasion of Iraq.

The State Department on Wednesday ordered the evacuation of non-emergency staff from the U.S. Embassy in Iraq, where a number of Iranian-allied militias operate. The department also urged Americans not to travel to Iraq.

The Trump administration also has sped up the deployment of an aircraft carrier to the Persian Gulf, while reportedly drafting plans for sending tens of thousands of troops to the Middle East.

It's difficult to tell, however, how serious the alleged Iranian threats are, and whether the administration's response so far has been proportional. The president himself appears hesitant to engage Iran in a military conflict. But some of his top aides, especially National Security Adviser John Bolton, have in the past championed the idea of toppling Iran's regime by force.

Iran has responded to the Trump administration's rhetoric with a mixture of mockery and bellicosity, but always insisting it wants no part in a war with the U.S.

Still, there's fear a war could evolve inadvertently if lower-level fighters on either side make moves that lead to a military response.

Democrats challenging Trump for the presidency in 2020 quickly jumped into the fray, comparing the burgeoning situation to the run-up to the U.S. invasion of Iraq. They noted that several top Trump staffers, including Bolton, pushed for the U.S. invasion of Iraq based on faulty — and possibly manipulated — intelligence that Iraqi dictator Saddam Hussein had weapons of mass destruction.

The U.S. can't make the same mistake on Iran, a harder target than Iraq, they said.

"It's time to end the forever wars," 2020 candidate Pete Buttigieg wrote on Twitter. "But in this White House, some of the same people who got us into Iraq now seem ready to stoke a new conflict. It's another reason Congress must reassert its war powers."

"This is chicken hawks trying to drag us into a war with Iran just like they did 15 years ago in Iraq," said Representative Seth Moulton of Massachusetts, a 2020 Democrat who has been highlighting his military service.

Some U.S. allies have also appeared hesitant to take the Trump administration at its word about imminent Iranian threats in the region.

A British major general, Chris Ghika, who is a top official in the U.S.-led battle against the Islamic State terrorist group, told reporters Tuesday there is "no increased threat from Iranian-backed forces" to U.S. and other coalition troops in Iraq and Syria. Ghika quickly walked back his comments, insisting there is no dissension between the U.S. and Britain on the subject, but U.S. military officials still issued a rare rebuttal of his remarks later that afternoon.

"There's concern of the rhetoric on both sides. We have to know what's going on. And we don't know" — Rhode Island Senator Jack Reed

European diplomatic officials, meanwhile urged Secretary of State Mike Pompeo to exercise "maximum restraint" with Iran after he flew to Brussels to brief them this week, a nod to the Trump administration's "maximum pressure" campaign against Iran.

America's European allies "do not see the same threat that this administration is talking about," said Ben Rhodes, a top aide to former President Barack Obama, Wednesday on MSNBC.

Rhodes added that during his eight years in the White House, "there was always intelligence about one particular group or another that could pose a threat to U.S. interests in the region from Iran or one of its proxies. That's not new."

But some U.S. and foreign diplomats privately told POLITICO the threats are credible, noting that the diplomatic security division of the State Department is known for its caution on such matters.

How the U.S. reacts could depend on how it is defining the threat, and critics of the administration worry its parameters are far too wide.

In announcing the administration is speeding up the deployment of an aircraft carrier and other warships to the Middle East, Bolton said that "any attack on United States interests or on those of our allies will be met with unrelenting force."

Iran has links to an array of militias throughout the Middle East, but it is not always in direct command and control of their actions. The U.S. also has many allies in the region, including Saudi Arabia, the United Arab Emirates and Israel, whose own military forces are in multiple places, raising the risk of contact with Iran or its proxies.

Trump on Tuesday denied a New York Times report that he is considering sending some 120,000 troops to the Middle East to counter the Iranian threat. But he didn't rule it out, either.

"Now, would I do that? Absolutely," Trump said. "But we have not planned for that. Hopefully we're not going to have to plan for that. If we did that, we would send a hell of a lot more troops than that."

A massive build-up of U.S. troops would take many months, but the 120,000 figure is widely believed to be an inadequate number for a full-on invasion of Iran, a country that is larger in size and population than Iraq, with a far more sophisticated military apparatus.

Iranian officials dismissed the notion that the two countries will go to war, while still saying they would prevail in any encounter.

"We don't seek a war nor do they. They know a war wouldn't be beneficial for them," Iran's Supreme Leader Ayatollah Ali Khamenei said Tuesday.

It's a back-and-forth that is causing hand-wringing back in Washington.

"There's concern of the rhetoric on both sides," said Rhode Island Senator Jack Reed, the top Democrat on the armed services committee. "We have to know what's going on. And we don't know."