"We want any kind of action. The world has stood silently and it's been too long. Something needs to be done," said Tamer Barazi, a 23-year-old civil engineer who carried a Syrian flag and a sign stating "Syrian Americans for peace, democracy and freedom in Syria."
Standing across the street in Houston's sweltering heat were those opposing U.S. intervention, outnumbering the supporters of an intervention. Some carried signs stating "We Don't Want Obama's War" and "Hands Off Syria."
"How would you like another country to decide who is going to be the president of the United States?" asked 53-year-old Hisam Saker, a Syrian-American property manager who has lived in Houston for 33 years.
In Washington, as Obama addressed the nation from the Rose Garden, anti-war demonstrators chanted and waved placards outside the White House.
Across the street, Syrians and Syrian Americans who support U.S. action waved flags from their country and shouted for Assad's ouster.
"The conflict's been going on for, what, almost 2 years now. Estimates are 100,000 Syrian civilians have been killed and all of a sudden the U.S. government has manufactured the excuse of the use of chemical weapons in Syria to use that excuse to intervene in Syria," said Tristan Brosnan, 25, of Washington.
In Boston, more than 200 protesters demonstrated in the Boston Commons against the possible use of force against Syria by the U.S. They waved signs and chanted "Don't Bomb Syria!" over and over again, and at least one speaker said congressional authorization wouldn't make an attack acceptable.
More than two dozen protesters gathered at the Arkansas Capitol to oppose a possible U.S. attack. Some wore T-shirts proclaiming "NO U.S. INTERVENTION IN SYRIA."
"I had friends that died in Iraq, and I don't want more people to die for nothing," said Dominic Box, 23, expressing some of the fears of a war-weary public.
In downtown Chicago, about 40 people walked quietly in the rain, circling a sculpture in Daley Plaza. Some carried signs that read "No War In Syria" and "Shut It Down."
"I don't believe in spreading democracy the way they're doing it," said Tyke Conrady, 44, who attended the protest with three friends.
In London, more than 1,000 protesters carrying Syrian flags and placards marched to Downing Street and rallied in Trafalgar Square. Some hailed the parliament's vote Thursday against British participation as a victory.
And about 700 people turned out for an anti-war demonstration in Frankfurt, Germany, police said. Organizers said only a "sovereign, independent Syria free of foreign interference" would make it possible for the Syrian people to shape the country's future.
At a protest organized by left-wing opposition parties in Amman, Jordan, Kawthar Arrar described any military intervention as "an aggression on the whole Arab world." The protesters gathered outside the U.S. embassy, chanting slogans and setting fire to American and Israeli flags.