Scores of pro-Palestinian protesters clashed with police outside the national headquarters of the Democratic Party in a melee that forced a lockdown of nearby offices of the US Congress, AFP reports.

“Our officers are working to keep back approximately 150 people who are illegally and violently protesting” near the party offices, the US Capitol Police said, adding that officers are making arrests.

Police escorted legislators who were at the Democratic National Committee (DNC) offices at the time out of the building to safety.

Six police officers were treated for injuries “ranging from minor cuts to being pepper sprayed to being punched,” Capitol Police said later in the evening after protesters were cleared out.