Groups of protesters took to the streets in Washington, New York and Lonon on Saturday to condemn the air strike in Iraq ordered by President Donald Trump that killed Iranian military commander Qassem Soleimani and Trump's decision to send about 3,000 more troops to the Middle East, reports Reuters and Anadolu Agency.
"No justice, no peace. US out of the Middle East," hundreds of demonstrators chanted outside the White House before marching to the Trump International Hotel a few blocks away.
Similar protests were held in New York, Chicago and other cities. Organisers at Code Pink, a women-led anti-war group, said protests were scheduled on Saturday in numerous US cities and towns.
Protesters in Washington held signs that read "No war or sanctions on Iran!" and "US 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 US 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 US 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. Thousands mourned his death in Iraq, Iran and Gaza. The Pentagon accused Soleimani of plotting the embassy attack and planning to carry out additional attacks on US diplomats and service members in Iraq and the region.
Showing no signs of seeking to reduce tensions, the US president has since issued a stern threat to Iran on Twitter, saying that the US has targeted 52 Iranian sites that it would strike if Iran attacks Americans or US assets in response to the US drone strike that killed Soleimani. He later added that the US will use 'new' equipment to strike Iran.
Public opinion polls show Americans in general have been opposed to US 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.