Chanting anti-American slogans, thousands of Iraqis converged on a landmark square in central Baghdad on Sunday to commemorate the anniversary of the killing of a powerful Iranian general and a top Iraqi militia leader in a U.S. drone strike. Roads leading to Tahrir Square were closed off and security was tight as the crowds gathered in response to a call by powerful Iran-backed militias for a rally marking the occasion and demanding the expulsion of U.S. troops from Iraq.

“No, no to America!” shouted some in the largely mask-less crowd. “You killed our guest. There is no place here for your embassy,” read some of the banners. Protesters at one point set fire to a large U.S. flag, drawing cheers from the crowd. The killing of Gen. Qassim Soleimani and Abu Mahdi al-Muhandis at Baghdad’s airport pushed Tehran and Washington perilously close to all-out conflict and sparked outrage in Iraq, leading parliament to pass a non-binding resolution days later calling for the expulsion of all foreign troops from Iraq.

Already, America has conducted B-52 bomber flyovers and sent a nuclear submarine into the Persian Gulf over what Trump officials describe as the possibility of an Iranian attack on the anniversary of the strike that killed Soleimani and al-Muhandis.

Carrying Iraqi and militia flags and posters of the two men, thousands of Iraqis marched toward Tahrir Square for the rally Sunday, demanding the withdrawal of U.S. troops in implementation of the parliamentary resolution. The event was organized by mostly Iran-backed militias known as the Popular Mobilization Forces.

“We call upon the government and the parliament to expel the occupying foreign forces, especially the brutal American forces, the infidels, the immorals, who killed the heroes and leaders of victory,” said Muhammad Shubr al-Husseini, a protester.