Indonesian security forces are behind the unlawful killing of at least 95 people in Papua since 2010 claims Amnesty International.
Papua, on the western half of New Guinea island, has been the scene of a simmering independence insurgency since it was annexed by Indonesia in the late 1960s.
Political activists and demonstrators peacefully protesting the government were among those killed in recent violence, as well as residents involved in non-political gatherings in Indonesia's easternmost province, the rights group said.
Not one case has been subject to an independent criminal investigation, according to Amnesty, which said it spent two years interviewing victims' families, witnesses, rights organisations, political activists and church-based community groups.
"Papua is one of Indonesia’s black holes for human rights. This is a region where security forces have for years been allowed to kill women, men and children, with no prospects of being held to account," Amnesty Indonesia executive director Usman Hamid said in a statement.
"This culture of impunity within the security forces must change, and those responsible for past deaths held to account."
Muhammad Aidi, the army’s spokesman for Papua province, said the allegations of unlawful killings and excessive force by security forces were inaccurate.
"Anything done by the army or police in Papua -- as well as throughout Indonesia -- must be legal [and] must follow legal process," Aidi told AFP.
Amnesty said 39 deaths were linked to peaceful political activities including raising the Morning Star, Papua’s banned flag.
Another 56 killings involved excessive use of force by the army or police and were unrelated to calls for independence.
Some of the violence has been centred on protests against a huge gold and copper mine owned by US-based firm Freeport McMoRan -- a frequent flashpoint in the local struggle for independence and a bigger share of the region's rich resources.
President Joko Widodo promised to improve human rights in amnesty international
Papua after taking office in 2014, but Amnesty says he has not lived up to his pledge.
It urged the Indonesian government to immediately investigate alleged killings and rights violations, as well as review tactics used by security forces.