Sporadic gunfire broke out in the centre of Monrovia on Monday after Liberian riot police fired tear gas to disperse several hundred supporters of presidential challenger Winston Tubman, a Reuters witness said.
A Liberian police officer said both the police and Tubman's CDC party supporters had fired but it was not possible to confirm the information.
Two United Nations helicopters flew overhead as police and Tubman's rock-throwing supporters clashed in side streets. Reuters journalists saw several people injured, including two police officers. A U.N. vehicle had been attacked.