Turkey says autopsies were carried out on three bodies that were brought across the border after Idlib attack.
Protesters held signs reading “Assad Out Now” and “Syrian Genocide”.
Tuesday’s attack on the town of Khan Sheikhoun in northern Syria which killed more than 80 people drew international condemnation and prompted President Donald Trump to launch cruise missiles on a government-controlled airbase.
Farouk Belal, an activist who helped organise the protest and who is a member of the Coalition for a Democratic Syria, said he and other Syrians in the DC area are calling for Assad’s ouster by military force to end the war and stop the proliferation of “extremist” organisations.
“The rise of ISIL is due to Assad’s crimes … As long as these crimes continue, people will join any group to fight him,” Belal, who is originally from Idlib, told Al Jazeera.
Belal said he was with some 20 other Syrian activists as news broke that 59 Tomahawk cruise missiles had been launched from US vessels in the Mediterranean Sea.
“We all felt the same thing, we were very sad that our home country was being bombed. We aren’t sure to be sad or happy. But we also want Assad to feel pain and be punished … So it’s a very confusing feeling.
“Stepping away from emotions, yes it’s good. At least Trump did something, Belal said.
“The hope is that President Trump continues this attack and hurts Assad more so that he can sit at the table and negotiate peace.”
Bassam Rifai, a spokesperson for the Syrian American Council, a grassroots organisation that advocates for a “a free, democratic, and pluralistic Syria through American support”, said the strike was “the first piece of hope Syrians have had” since the civil war started in 2011.
“President Trump just started to do in two days what we’ve been asking for six years,” he told Al Jazeera.
“We want no-fly zones, air strikes against runways, no more hitting civilian areas and hospitals. We want the entire [Syrian] air force to be grounded so they can’t carry out attacks against civilians.”
No-fly zones were discussed extensively before Russian air forces entered the civil war.
When asked how effective a no-fly zone for Syrian warplanes would be with Russians still providing support, Rifai said “it becomes a touchy situation. But because we have a different relationship with Russia, it’s a negotiation to be had,” referring to warmer relations between the Trump administration and Moscow than under previous administrations.
“Russia just said its support for Assad isn’t unconditional. That was unthinkable a week ago,” Rifai added.
Military intervention is a contentious subject for many in the US, who are still wary from wars in Iraq and Afghanistan that have gone on for more than a decade.
The six-year civil war in Syria has killed an estimated 500,000 people. Another 11 million people have fled their homes.
Follow Creede Newton on Twitter: @creedenewton