Police fire tear gas at protesters trying to storm government HQ in Bangkok

Anti-government protesters try to remove police barricade during a rally in front of the Department of Special Investigation in Bangkok, Thailand, Saturday, Nov. 30, 2013. Anti-government protesters in Thailand placed symbolic padlocks on the doors of several state-run offices, continuing a week-long campaign to paralyze the administration of Yingluck Shinawatra.(AP Photo/Wason Wanichakorn) (The Associated Press)

An anti-government protester attacks people they suspected of supporting the current Thai government on the bus in Bangkok,Thailand Saturday, Nov. 30, 2013. A mob of anti-government protesters smashed the windows of a moving Bangkok bus Saturday in the first eruption of violence after a week of tense street protests.(AP Photo/Wason Wanichakorn) (The Associated Press)

Anti-government protesters gather in front of the Democracy Monument during a rally in Bangkok, Thailand, Sunday, Dec. 1, 2013. 2013. Aggressive political protests in the Thai capital turned violent late Saturday with at least one man killed and several wounded by gunshots in street fighting between supporters and opponents of Prime Minister Yingluck Shinawatra. (AP Phoito/Sakchai Lalit) (The Associated Press)

Riot police in the Thai capital have fired tear gas at protesters trying to force their way into the prime minister's office compound and Bangkok police headquarters.

Reporters saw anti-government protesters trying to rip down concrete barriers outside the Government House on Sunday. Police fired tear gas and water cannons to push them back.

Separately, police drove back another crowd of protesters at the Bangkok police headquarters.

This was the first time police have used force against protesters who have occupied government offices for the past week in a bid to topple Prime Minister Yingluck Shinawtra.