JAKARTA - Indonesia police used teargas and water cannon on Monday to disperse hundreds of demonstrators who massed outside the U.S. embassy in Jakarta to protest against a film mocking the Prophet Mohammad.

One policeman was injured by stones thrown by protesters and a handful of demonstrators were detained, television pictures broadcast live from the scene showed. Protesters burned a US flag.

Western embassies across the Muslim world are on high alert and the United States has urged vigilance after days of anti-American violence provoked by the film.

Indonesia, a secular state, is the world's fourth largest country by population and has the largest population of Muslims. It also has significant minorities of Hindus, Buddhists and Christians.