Anyone who attacks the U.S. Embassy in Baghdad, Iraq, will run into a “buzz saw,” the Chairman of the Joint Chiefs of Staff warned on Thursday.

“We are very confident in the integrity of that embassy,” Army Gen. Mark Milley told reporters during a morning briefing at the Pentagon. Milley held the briefing along with Defense Secretary Mark Esper following Tuesday's attack on the embassy compound. Hundreds of aggressors attacked the compound in response to American airstrikes on Kataib Hezbollah. The United States sent 100 Marines and two Apache helicopters to help reinforce the compound and additionally dispatched 750 soldiers from the Army’s 82nd Airborne Division.

It is “highly unlikely” anyone will be able to overrun the embassy compound, Milley said at the briefing, adding that anyone who attempts to do so “will run into a buzz saw.”

The aggressors in Baghdad were led by Qais al Khazali, an Iranian-backed Iraqi terrorist turned politician. The group besieged the embassy compound, lighting fires and chanting “Death to America!” — a common refrain heard in Iranian rallies.

“Americans are unwanted in Iraq,” Khazali told Reuters on Tuesday. “They are a source of evil, and we want them to leave.”

Why Iraqi forces did not repel the attack remains unclear. Typically, the country wherein an embassy is located is tasked with providing outer security to the facility. American embassies additionally are protected by a small contingent of Marines and other security personnel.

The Iraqi Security Forces are capable of protecting the embassy, Milley said at the briefing. It is more a question of “political will, and that’s not for us to decide,” he said.

There are “indications” that Iranian-backed forces may conduct further attacks, Esper reportedly said at the Thursday morning briefing, adding that the U.S. is prepared to defend its interests.

“The game has changed, and we’re prepared to do what is necessary to defend our personnel and our interests and our partners in the region,” Esper added.

[ Opinion: Iran faces hard choices against America in Iraq]