Authorities used pepper spray on a group of protesters trying to enter the National Air and Space Museum on Saturday , forcing the building to close about two hours early . One person was arrested , according to Linda St. Thomas , a spokeswoman for the Smithsonian Institution , which runs that and numerous other museums in Washington . She estimated between 100 and 200 people were in the crowd . Demonstrators railing against U.S. participation in the war in Afghanistan initially gathered Saturday , along with protesters aligned with the national Occupy Wall Street movement , in Washington 's Freedom Plaza . The latter effort started in New York more than three weeks ago , targeting the nation 's financial sector and various social ills , and has since spread to more than a dozen cities . The Washington demonstrators Saturday chanted `` Occupy Wall Street , Occupy H Street , Occupy Everything , and never give it back . '' Some moved from Freedom Plaza toward the museum , which is along the National Mall , escorted by District of Columbia police . Some started to enter the museum to demonstrate against displays of military drones used during the war in Afghanistan . St. Thomas said that one of the protesters pushed a museum security guard against a wall , prompting another guard to respond with pepper spray to force demonstrators outside . `` We wanted to go inside and protest at those particular items of destruction , and the crowd was pepper sprayed going in and was forced out of the building , '' said Brian Morrison , one of the protesters . See video of the protest . Araz Alali , a spokesman with the D.C. Police , said his department had no knowledge the museum security was going to pepper spray the protesters . Demonstrator Greg Slater carried a sign that read `` Occupy Wall Street , not Afghanistan . '' He said that the protest did not warrant the type of reaction it got from the museum security guards . `` This is absolutely meant to be a nonviolent protest , '' said Slater . `` It 's about peacefully taking back of democracy and ending the war in Afghanistan . '' St. Thomas said that the Air and Space Museum will open at its regularly scheduled time of 10 a.m. Sunday .
Anti - war and Occupy Wall Street - aligned protesters march in Washington . Some refuse to enter the Air and Space Museum over its military aircraft display . A guard pepper sprayed after another guard was pushed , a museum spokesman says . The museum closed early Saturday , but is expected to reopen on a Sunday .