Donald Trump has decided to send 3,000 more troops to the Middle East after the killing of Iranian General Qassem Soleimani.
Groups of protesters took to the streets in Washington and other US cities today to condemn the decision - as well as the US President's decision to order the air strike that killed the military commander.
"No justice, no peace. U.S. out of the Middle East," hundreds of demonstrators chanted outside the White House before marching to the Trump International Hotel a few blocks away.
Protesters in Washington held signs that read "No war or sanctions on Iran!" and "U.S. troops out of Iraq!"
Speakers at the Washington event included actress and activist Jane Fonda, who last year was arrested at a climate change protest on the steps of the U.S. Capitol.
"The younger people here should know that all of the wars fought since you were born have been fought over oil," Fonda, 82, told the crowd, adding that "we can't anymore lose lives and kill people and ruin an environment because of oil."
"Going to a march doesn't do a lot, but at least I can come out and say something: that I'm opposed to this stuff," said protestor Steve Lane of Bethesda, Maryland.
"And maybe if enough people do the same thing, he (Trump) will listen."
Soleimani, regarded as the second most powerful figure in Iran, was killed in the U.S. strike on his convoy at Baghdad airport on Friday in a dramatic escalation of hostilities in the Middle East between Iran and the United States and its allies.
Public opinion polls show Americans in general have been opposed to U.S. military interventions overseas.
A survey last year by the Chicago Council on Global Affairs found 27% of Americans believe military interventions make the United States safer, and nearly half said they make the country less safe.
On Saturday evening, a rocket fell inside Baghdad's heavily-fortified Green Zone near the US Embassy, another hit the nearby Jadriya neighbourhood and two more rockets were fired at the Balad air base north of the city, but no one was killed, the Iraqi military said in a statement.
There was no immediate claim of responsibility.
With security worries rising after Friday's strike, the NATO alliance and a separate U.S.-led mission suspended their programmes to train Iraqi security and armed forces, officials said.
"The safety of our personnel in Iraq is paramount. We continue to take all precautions necessary," acting NATO spokesman Dylan White said in a statement.
