The Pentagon issued a stern warning against future attacks on US diplomatic outposts in Iraq, with the chairman of the Joint Chiefs of Staff, Gen. Mark Milley, telling reporters on Thursday that "anyone who attempts to overrun" the US Embassy in Baghdad "will run into a buzzsaw."

In response to violent protests outside the embassy on Tuesday, the US dispatched about 100 Marines to reinforce the position and deployed hundreds of Army paratroopers to the Middle East to boost security.

"The game has changed. We're prepared to do what is necessary," Secretary of Defense Mark Esper said on Thursday.

Visit Business Insider's homepage for more stories.

The Pentagon warned on Thursday morning that anyone who tries to breach the US Embassy in Baghdad would face a "buzzsaw."

Swarms of violent protesters and apparent supporters of an Iran-backed Iraqi militia targeted by recent US airstrikes stormed the gates of the embassy on Tuesday, forcing the Pentagon to react.

About 100 Marines from a special crisis-response unit created after the 2012 attacks on US diplomatic posts in Benghazi, Libya, were sent in to reinforce the embassy, and 750 paratroopers from the Army 82nd Airborne Division's Immediate Response Force deployed to the US Central Command area of operations.

At a press briefing on Thursday, the chairman of the Joint Chiefs of Staff, Gen. Mark Milley, said that "we are very confident in the integrity of that embassy."

"It is highly unlikely to be physically overrun by anyone," he said, adding that "anyone who attempts to overrun that will run into a buzzsaw."

The US on Sunday conducted airstrikes against five positions of the militia, Kataib Hezbollah, in retaliation for a rocket attack days earlier on an Iraqi base that killed a US contractor and wounded several American service members.

President Donald Trump has pinned the blame for both the rocket attack and the assault on the embassy on Iran.

"Iran killed an American contractor, wounding many. We strongly responded, and always will. Now Iran is orchestrating an attack on the U.S. Embassy in Iraq. They will be held fully responsible," he tweeted on Tuesday, later adding: "Iran will be held fully responsible for lives lost, or damage incurred, at any of our facilities. They will pay a very BIG PRICE! This is not a Warning, it is a Threat."

The past year has been largely characterized by heightened tensions with Iran, which the US military has deployed roughly 15,000 troops to counter since May.

Secretary of Defense Mark Esper said at the briefing on Thursday, according to Voice of America, that the US would "take preemptive action" against Kataib Hezbollah and other Iran-backed militias in Iraq "to protect American forces, to protect American lives."

He added: "The game has changed. We're prepared to do what is necessary."

Esper said that there were indications that groups opposed to the US presence in the area might be planning additional attacks.

"Do I think they may do something? Yes. And they will likely regret it," he said.

The Department of State told Insider on Wednesday that the situation at the embassy "has improved" and that the Iraqi security forces had stepped in to provide additional security, clearing protesters away from the outpost.

The embassy, which cost an estimated $750 million, is in a 104-acre compound in the fortified Green Zone, making it the world's largest embassy.

"Though the situation around the Embassy perimeter has calmed significantly, post security posture remains heightened," the emailed statement read. The Pentagon has left the door open to sending more troops to the Middle East to counter threats to US personnel in the region.