The U.S. military put its forces in Iraq on high alert, and the State Department ordered all nonemergency employees Wednesday to leave the country immediately amid escalating tensions with Iran. Some U.S. allies have expressed skepticism about the Trump administration’s claims that Iran poses a growing threat.

Navy Capt. Bill Urban, a spokesman at the U.S. military’s Central Command, said in a statement that there were "possibly imminent threats to U.S. forces in Iraq" as he sought to clarify contradictory remarks by a British commander Tuesday.

British Maj. Gen. Christopher Ghika, a senior officer in the U.S.-backed coalition fighting the Islamic State group in Iraq and Syria, said, "There’s been no increased threat from Iranian-backed forces in Iraq and Syria." Urban rebutted Ghika's remarks in a sign of how the United States and its close allies have split over Iran's potential threat.

Applying "maximum pressure" on Iran is a central tenet of the Trump administration's foreign policy. Trump withdrew the United States from a nuclear deal reached between Iran and world powers in 2015, reimposed crushing sanctions and boosted the U.S. military presence in the Persian Gulf. Unease that Washington and Tehran could be headed toward military confrontation has mounted.

Iran to Trump: You are playing 'very dangerous game,' risking 'devastating war'

In Baghdad, the U.S. Embassy published a statement Wednesday saying the State Department mandated that all nonemergency government staff leave the country after Washington said last week it detected urgent "credible" threats from Iran and its proxy forces in the region targeting Americans and U.S. interests.

Specific details about the intelligence have not been revealed.

Saudi Arabia said this week that two of its oil tankers and other energy-related infrastructure were damaged in an act of "sabotage" in the Gulf. Yemen's Iran-backed Houthi rebels, who are fighting a war with Saudi Arabia, claimed responsibility for drone attacks on Saudi oil facilities Tuesday.

Federica Mogherini, Europe's top foreign affairs diplomat, called for the United States to show "maximum restraint" after meeting with U.S. Secretary of State Mike Pompeo.

Mixed messages:Varied points of view from Trump on Iran

When the United States pulled out of the nuclear deal in May last year, the other signatories to the accord – Britain, China, France, Germany, Russia and the European Union – vowed to stay in and establish a financial mechanism that would allow them to keep trade and other ties with Iran open amid the U.S. sanctions. They have struggled to achieve that. As a result, Iran gave European countries 60 days to find a way of salvaging the agreement or it would start enriching uranium to far higher levels.

If nothing happens when the 60 days are up, "there will be consequences from our side," Hamid Baeidinejad, Iran’s ambassador to the United Kingdom, told USA TODAY and other media outlets during a briefing in Iran's Embassy in London on Tuesday.

Successive U.S. administrations have viewed Iran as a regional troublemaker and described it as the "largest state sponsor of terrorism." Tehran aids a number of Shiite militant groups in Iraq, Lebanon, Syria and elsewhere across the Middle East. The Trump administration pulled out of the nuclear deal in part because of that and also because the deal does not address Iran's ballistic missile activity.

Iran or its proxies, such as Hezbollah, Hamas and the Taliban, have carried out bombings, abductions and hijackings against the USA and other Western nations.

"Iran is certain to continue to pursue its regional strategy, unless and until its adversaries are willing or able to blunt Iran’s efforts," the authors of a new report by the Soufan Center, a global security research center, wrote. "Rolling back Tehran’s regional influence will require an equally nimble approach combining diplomacy, smart counter-terrorism policy, and a nuanced understanding of how and why Iran’s soft power efforts have been successful so they may be effectively countered."

New Jersey Sen. Bob Menendez, the top Democrat on the Senate Foreign Relations Committee, said lawmakers needed an immediate briefing from Trump administration officials on the alleged threats from Iran. He said there are only two reasons for the State Department to order the departure of U.S. Embassy staff from Baghdad: credible intelligence Americans are at risk or preparation for military action.

"The Trump administration has not provided any information to this committee on the intelligence behind their decisions or what they plan to do in Iraq or Iran," he said.

War plan?:Trump dismisses report of plan to send troops to Middle East

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Contributing: Deirdre Shesgreen