There were unconfirmed reports that at least three people were killed. The students were protesting at a state security Bill widening the powers of the already powerful military.
Many Indonesians fear a coup by stealth and the rollback of democratic gains achieved since the overthrow of the Suharto regime.
Serious injuries were reported. Witnesses saw protesters taken to hospital with bullet wounds.
Local news agencies said that the clashes began when riot police stopped demonstrators converging on parliament. The students were held back by police firing in the air. They were then tear-gassed, which provoked a hail of stones and petrol bombs as the protesters tried to stand their ground.
The Bill, which will become when President B J Habibie signs it, will beef up army powers to arrest and detain under any state of emergency the President agrees to impose.Reuse content