"Our first priority is the safety and security of US personnel," a State Department spokesperson said in a statement.

"US personnel are secure and there has been no breach," the spokesperson said. "There are no plans to evacuate Embassy Baghdad."

The US ambassador to Iraq, Matt Tueller, who had been away on "personal travel," was returning to the embassy, the spokesperson added.

Defense Secretary Mark Esper said that the Pentagon is deploying extra troops to Baghdad to provide security for the US embassy after the attack by pro-Iran protesters angered by US airstrikes over the weekend on Iranian-backed paramilitary forces.

"The Department of Defense is working closely with the Department of State to ensure the security of our Embassy and personnel in Baghdad," Esper said in a statement.

"We are sending additional forces to support our personnel at the embassy."

Esper gave no details, but the deployment is likely to involve a small number of US Marines, according to a US defense source.

"We have made clear the United States will protect and defend its people, who are there to support a sovereign and independent Iraq," the State Department spokesperson said.

"We are closely monitoring the situation in Iraq and call on the Government of Iraq to protect our diplomatic facilities per their obligations."

The State Department also said the "Iranian backed demonstrations in front of the US Embassy should not be confused with the Iraqi protestors who have been in the streets since October to decry the corruption exported to Iraq by the Iranian regime."