Jakarta – Indonesia should release three men imprisoned for raising a banned separatist flag because the harsh punishment undermines the country's democratic values, a prominent rights groups said Thursday.

President Susilo Bambang Yudhoyono should overturn the prison terms of up to three years handed down last week for using the symbol of a small movement seeking to break from the central government, the New York-based Human Rights Watch said.

"These prosecutions fly in the face of Indonesia's commitments to free expression," said Elaine Pearson of Human Rights Watch. "Yudhoyono should have these men freed without delay."

More than 170 people are currently jailed in Indonesia for peaceful expression, mostly in Papua and Maluku, where there is also a small separatist movement, the group said. Indonesian authorities are highly sensitive to secessionist issues, cracking down on protesters and prohibiting foreign journalists from travel to Papua. Last year, an Indonesian court sentenced a group of separatists to between 10 years and life in prison for waving their flag in front of the president in the Maluku islands.

The three Papuans have been detained since early this year after hoisting a flag resembling the "Morning Star" that is used by the banned Free Papua Movement rebels.

Two other men were charged Wednesday in another flag-raising incident in Papua and could face up to 12 years in prison, said police official Bambang Rudy Pratikno.

A low-level insurgency had waged for decades in Papua, an impoverished province on Indonesia's easternmost tip.

Human Right Watch said more flag-raising ceremonies were expected before Dec. 1, which many Papuans see as an anniversary marking independence from Dutch colonial rule. Pratikno said police were on alert for rallies attended by separatists.

Although Indonesia has made progress in human rights since becoming a democracy more than a decade ago, abuse by the police and military are still a major concern.