After vowing to camp outside the US embassy until the Americans left Iraq, and trying for a second day to scale the compound’s walls, demonstrators drawn largely from Iranian-backed militias called off their protest on Wednesday.

They gradually drifted away on foot or drove off in trucks, ending a tense standoff in which American diplomats were trapped in the embassy compound, and US troops fired tear gas to disperse the thousands of people who stood outside chanting “Death to America.”

Iraqi counterterrorism forces took over on Wednesday from the Special Forces for the Green Zone, which had largely hung back from confronting the protesters, even as some of them attempted to climb over the walls and clambered onto the roof of the reception building demonstrators had burned a day earlier.

In contrast to Tuesday, when some demonstrators forced their way into the compound and lit fires there, the crowd was much smaller on Wednesday and none of the protesters got inside the compound.

When they reached the roof of the burned reception building, the US security forces defending the embassy shot tear gas that drove them back, and a second volley of tear gas around midday dispersed a few hundred of the roughly 1,000 who had spent the night just outside the walls.

A couple of hours later an order came from the Hashid Commission, which oversees all the armed groups that sprang up in 2014 to fight the Islamic State — the most powerful of which are close to Iran and function as Iranian proxy forces.

The commission asked, out of “respect for the government’s sovereignty” and its promise that “it had heard the protesters’ message”, that the protesters stand down. That request was reiterated by the spokesman for one of the powerful, Iranian-backed armed groups, Asaib al-Haq.