Eyewitnesses say police in riot gear went on a three-hour tear-gassing spree in heart of Zimbabwe's capital.

The battles broke out Tuesday after authorities tried to confiscate vendors' wares and they resisted. Witnesses say the vendors then threw bricks in retaliation, and police began tear gassing them along with shoppers.

The commotion brought business in central Harare to a halt for several hours.

Police then went on to raid Prime Minister Morgan Tsvangirai's party headquarters, accusing guards there of harboring the vendors.

Rights activists say it is just another example of how police are harassing Tsvangirai's supporters.

Tsvangirai formed a shaky coalition government with longtime President Robert Mugabe in 2009 after violent, disputed 2008 elections.