U.S. Capitol Police (USCP) officers in riot gear clashed with roughly 200 demonstrators who gathered outside the Democratic National Committee (DNC) headquarters in Washington on Wednesday evening to demand a cease-fire in Gaza.

The protest was organized by three advocacy groups and held in an area near the U.S. Capitol. Lawmakers who were inside the DNC building said police had evacuated them from the area.

Six officers were treated for injuries, from minor cuts to being pepper sprayed to being punched, USCP said.

"We have handled hundreds of peaceful protests, but last night's group was not peaceful. The crowd failed to obey our lawful orders to move back from the DNC, where Members of Congress were in the building," the Capitol Police said in a statement posted on X, formerly known as Twitter.

Protesters linked arms in front of the DNC building's entrance, where some sang: "Which side are you on?" Officers pushed and pulled the protesters to try to remove them from the area, at one point shoving one protester down a staircase leading to the entrance.

"When the group moved dumpsters in front of the exits, pepper sprayed our officers and attempted to pick up the bike rack, our teams quickly introduced consequences – pulling people off the building, pushing them back, and clearing them from the area, so we could safely evacuate the Members and staff," USCP said.

"One person has been arrested for assault on an officer."

Ruben Arthur Camacho, 24, of Woodbridge, N.Y., was arrested for assaulting a police officer after Camacho was seen slamming another officer into a garage door and then punching the female officer in the face.

The organizers rejected allegations that demonstrators were violent.

Public demonstrations — both pro-Palestinian and pro-Israel — have rippled around the world since Hamas gunmen rampaged through southern Israel on Oct. 7, killing 1,200 people, according to Israel, and taking about 240 hostages back to Gaza.

Israel has retaliated with a strict blockade on Hamas-controlled Gaza, and an aerial bombardment and ground offensive that Palestinian authorities say has killed around 11,500 people, around 40% of them children.

Congressman Sean Casten said he was evacuated from the DNC building after it "was surrounded by protesters who had blocked all modes of ingress and egress."

He added: "We were rescued by armed officers who did not know the protesters’ intent; they knew only that Members of Congress were inside, could not leave and that protesters would not let police through."

A DNC spokesperson said officials were monitoring the situation outside the DNC headquarters and were in touch with U.S. Capitol and local Washington police.

The organizers of the protest were IfNotNow, which urges U.S. Jewish groups to end their support of Israel's policies toward the Palestinians, Jewish Voice for Peace, a group that advocates for Palestinian independence, and the Democratic Socialists of America.

Jewish Voice for Peace wrote on social media that the protesters had gathered to lay out candles for Palestinians killed during Israel's bombardment and to call for a ceasefire.