The Iraqi army shut down a demonstration in the town of Baiji on Friday in support of an autonomy bid by a Sunni province, but let an anti-autonomy protest go ahead, the town's mayor said.

On October 27, the council of Salaheddin province voted for it to become an administratively and economically autonomous region along the lines of Kurdistan in north Iraq, after security forces detained alleged members of Saddam Hussein's now-dissolved Baath party in the province.

"The two demonstrations were actually at the same place, but the Iraqi army ... said the pro-federalism demonstration was not licenced, while the other one got a licence," said Abid Awath, the mayor of Baiji, which is in Salaheddin.

A "few demonstrators were detained and released later on, but all leaflets were confiscated," Awath added.

Three large buses brought anti-federalism demonstrators in from the nearby town of Siniya, he said.

The Salaheddin vote has been strongly condemned by the central government, and the army action against the demonstrators may indicates that Baghdad's stance against the move is becoming harder still.

Under Article 119 of the Iraqi constitution, a province-wide referendum would need to be held before Salaheddin could become autonomous.