A crowd of hundreds of people gathered in front of the White House and marched through downtown D.C. to protest President Donald Trump’s decision to end the Deferred Action for Childhood Arrivals program, which leaves the fate of 800,000 people to the whims of Congressional action.

As details of the plan leaked, dozens of people held a vigil and protested outside the White House over the holiday weekend. That grouped swelled to hundreds after Jeff Sessions made the announcement this morning, calling DACA an “open-ended circumvention of immigration laws.”

After a series of speeches at the White House, protesters took to the streets, blocking traffic on Pennsylvania Avenue outside the Trump hotel on their way to ICE headquarters.

There are about 800 DREAMers living in D.C. according the administration of Mayor Muriel Bowser, with the total population of undocumented immigrants estimated at around 25,000 people.

The District has been a designated sanctuary city for decades, and Bowser has reiterated that commitment. The mayor announced a new grant program totaling $500,000 earlier this year to provide immigration-related legal services, and recently renewed the Immigrant Justice Legal Services Grant program for a second year.

The mayor wrote a Medium post last week saying “Washington, D.C. stands with DREAMers” as news of the impending plan trickled out, and she emphasized it again in a statement today.

“DACA has allowed young people-many who came to United States as very young children and know no other home-to get jobs, go to school, serve in the military, and become active members of their communities,” Mayor Muriel Bowser said in a statement. “We are proud of our DREAMers and our support will be unwavering.”