The police chief of Washington, D.C., says pro-Trump protesters deployed “chemical irritants” on police in order to break into the U.S. Capitol.

Police Chief Robert Contee says officials have declared the scene a riot. One civilian was shot inside the Capitol on Wednesday. Thirteen arrests were made of people from out of the area.

Mayor Muriel Bowser says the behavior of the Trump supporters was “shameful, unpatriotic and above all is unlawful.” She says, “There will be law and order and this behavior will not be tolerated.”

Metropolitan police have been sent to the Capitol, and authorities were coming in from Maryland, Virginia and New Jersey to help out. The National Guard was also deployed, as were Homeland Security investigators and Secret Service.

Trump had encouraged his supporters to come to Washington to fight Congress’ formal approval of President-elect Joe Biden’s win. He held a rally earlier Wednesday and urged his supporters to march to the Capitol, telling them to “get rid of the weak Congress people” and saying, “get the weak ones get out; this is the time for strength.”

Law enforcement appears to have cleared out the north side of the U.S. Capitol after hours-long standoff. Used flash bangs and tear gas to push people back. pic.twitter.com/GlR9VLVm9w

— Michael Brice-Saddler (@TheArtist_MBS) January 6, 2021