Soldiers and police were battling supporters of an alleged drug lord in the Jamaica capital, Kingston, with at least 30 people reportedly killed in the violence.
Many of the casualties were said to be civilians.
Prime Minister Bruce Golding declared a state of emergency in several districts of Kingston.
Tensions in Jamaica have risen since Golding announced he was starting proceedings to extradite Christopher "Dudus" Coke, who is wanted in the United States on cocaine-trafficking and gun-running charges.
compiled from agency reports