A bomb exploded in Bangkok early on Friday, seriously wounding a man and stoking fears of civil unrest following a deadly blast five days ago and violent anti-government protests in April and May.

Police said a grenade tied with an oiled rubber band and wrapped in a garbage bag exploded at about 2 a.m. (1900 GMT Thursday) in an alley near Victory Monument, an area usually choked with traffic and surrounded by government buildings.