Protesters broke into the United States Embassy in Baghdad and lit fires inside the compound on Tuesday, while thousands of people chanted “Death to America” outside.

President Donald Trump said the attack was orchestrated by Iran Tuesday and insisted the country would be held “fully responsible.”

U.S. Sen. Chris Murphy, D-Conn., called the attack “horrifying but predictable.” He blamed the Trump administration’s policy toward the Middle East for the assault on the embassy, while some Republicans praised the administration’s swift response to the onslaught.

“[President Donald] Trump has rendered America impotent in the Middle East,” Murphy, a member of the Senate Foreign Relations Committee, wrote in Twitter Tuesday morning. “No one fears us, no one listens to us. America has been reduced to huddling in safe rooms, hoping the bad guys will go away.”

The embassy siege came two days after a American airstrike killed two dozen members of a Iranian-backed militia. Secretary of State Mike Pompeo said Tuesday that airstrike was a defensive response to the militia’s attack that killed an American citizen and wounded U.S. and Iraqi soldiers.

“Iran killed an American contractor, wounding many,” Trump tweeted. “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. In addition, we expect Iraq to use its forces to protect the Embassy, and so notified!”

Pompeo spoke to the president and prime minister of Iraq to remind them of “their obligation to protect our U.S. personnel and property,” he said.

U.S. Sen. Lindsey Graham, R-S.C., another member of the Senate Foreign Relations Committee, said he was “very proud” of Trump for acting “decisively” in the face of attacks on the embassy.

“President Trump, unlike President [Barack] Obama, will hold you accountable for threats against Americans and hit you where it hurts the most,” Graham tweeted Tuesday. “Choose your battles wisely.”

Graham warned that a nation whose economy is dependent on oil like Iran needs to be “cautious” and urged Iraq officials to demonstrate their support for the U.S.-Iraq relationship by protecting American officials.

The conflict comes at a time when the U.S. and Iran are increasingly competing for political influence in Iraq, where the Islamic State once controlled large territories.

Murphy said the embassy battle on the last day of the year is a reminder of how “catastrophic” 2019 has been for U.S. interest in the Middle East, tweeting a list of 11 examples involving Iran, Saudi Arabia, Turkey, Yemen, Egypt, Israel, Palestine, Syria, Lebanon and other powers.

U.S. military forces have been present in Iraq for 16 years. About 5,000 U.S. troops remain in Iraq, as well as civilian contractors and American diplomats. The embassy attackers demanded that the U.S. withdraw from Iraq Tuesday.