(Adds details on body being moved through Tunis)
TUNIS, Feb 6 (Reuters) - Tunisian police fired teargas to disperse protesters demonstrating in the capital outside the Interior Ministry against the killing of a prominent secular opposition politician on Wednesday, witnesses said.
Police fired the teargas as an ambulance carrying Chokri Belaid's body approached Tunis's main street, where protesters had massed outside the ministry, they said.
The ambulance was carrying the body from the hospital where he died after being shot four times outside his home.
Police also fired in the air and used teargas in Sidi Bouzid, the birthplace of the Arab Spring uprisings, to disperse demonstrators.
(Reporting by Tarek Amara; Editing by Alison Williams)