The embassy said in a May 15 statement that the order applied to employees both at the embassy and at the U.S. Consulate in the northern city of Irbil, the capital of Iraq's Kurdish autonomous region.
U.S. Defends Gulf Military Buildup, Says It's 'Not Spoiling For Fight'
Tensions have been escalating between Iran and the United States since Washington a year ago withdrew from the 2015 nuclear deal between Tehran and world powers, and started reimposing sanctions against Iran.
Washington has ramped up pressure on Tehran in recent days, bolstering the U.S. military presence in the region to counter what U.S. officials called "imminent" threats from Iran against the interests of the United States or its allies.
Iran dismissed the allegations, and announced it was suspending some of its commitments it made under the nuclear agreement in exchange for sanctions relief.
On May 14, U.S. Secretary of State Mike Pompeo and Iranian Supreme Leader Ayatollah Ali Khamenei said in separate statements that their countries did not seek a war.
/**/ /**/ /**/ U.S. President Donald Trump: Hopefully, we're not going to have to plan for that." (file photo)
Trump Denies U.S. Preparing Plans To Send 120,000 Troops To Counter Iran Threat
Their comments came after Yemen's Iranian-backed Huthi rebels launched a drone attack on oil facilities in Saudi Arabia amid what has been called a proxy war between Saudi Arabia and Iran.
Saudi Aramco, the government-controlled oil company, said a fire caused minor damage to a pumping station. But it insisted that the attack would not affect Saudi oil supplies.
Details around alleged acts of sabotage to four oil tankers off the United Arab Emirates on May 13 remain unclear.
There were no casualties, but Saudi Arabia said two of its ships had suffered "significant damage."
In its statement, the U.S. Embassy in Iraq said that normal visa services at the Baghdad and Irbil diplomatic missions will be temporarily suspended.
It recommended those affected "depart by commercial transportation as soon as possible."
Meanwhile, the State Department issued a revised travel advisory saying, "Do not travel to Iraq due to terrorism, kidnapping, and armed conflict."
"Numerous terrorist and insurgent groups are active in Iraq and regularly attack both Iraqi security forces and civilians," it said. "Anti-U.S. sectarian militias may also threaten U.S. citizens and Western companies throughout Iraq."
Tehran is backing Shi'ite militia groups in Iraq. However, neither the embassy statement nor the State Department's travel advisory mentioned Iran by name.
Last week, Pompeo paid an unexpected visit to Baghdad, where he met with Iraqi officials to discuss U.S. security concerns amid what he called "escalating" Iranian activity.
He said the threat of attacks were "very specific," without providing details.
His visit came after Washington announced the deployment of an aircraft-carrier battle group and a B-52 bomber task force to the Persian Gulf region.
Asked about the decision, Pompeo said, "The message that we've sent to the Iranians, I hope, puts us in a position where we can deter and the Iranians will think twice about attacking American interests."
Tehran said Washington was engaging in "psychological warfare."
British Major General Chris Ghika, a senior officer in the U.S.-backed coalition fighting the Islamic State extremist group, said on May 14 that there had not been any "increased threat from Iranian-backed forces in Iraq and Syria."
The comments drew a rebuttal by the U.S. military, which said the remarks "run counter to the identified credible threats" posed by Iranian-backed forces in the Middle East.
Meanwhile, the German and Dutch militaries announced on May 15 that they had suspended training operations for Iraqi forces due to increasing regional tensions.
Some 160 German soldiers have been involved in the training mission.
German Defense Ministry spokesman Jens Flosdorff said there was "generally heightened alert, awareness" among soldiers in the region, but gave no specifics.
Separately, the Dutch Defense Ministry said it was suspending a training mission in Iraq due to "threats," according to the Dutch ANP news agency.
U.S. Central Command said the coalition had increased the alert level for all military service members in Iraq and Syria.
In announcing the U.S. withdrawal from the 2015 nuclear accord with Iran, President Donald Trump said the terms were not tough enough to prevent Iran from developing nuclear weapons and did not address Iran's missile program or Tehran's support for militants in the region.
Iran denies it supports insurgent activity and has said its nuclear program is strictly for civilian energy purposes.
Copyright (c) 2015. RFE/RL, Inc. Reprinted with the permission of RadioFree Europe/Radio Liberty, 1201 Connecticut Ave NW, Ste 400, Washington DC 20036.