The Burmese government could have prevented the recent sectarian violence in Arakan state, which killed at least 78 people and displaced 100,000, but instead stood by and watched abuses perpetrated against both Arakanese and Rohingya communities, according to Human Rights Watch (HRW).

A new report, based on 57 interviews with Arakanese and Rohingya witnesses in Burma and Bangladesh, accuses the government of failing to stop the escalating conflict, and later playing a direct role in targeting the stateless minority group.

“Witness after witness described to Human Rights Watch how the Burmese authorities failed to provide protection to either side in the early days of the violence and that Arakan and local security forces colluded in acts of arson and violence against Rohingya,” said the report.

Tensions flared in the western state after the rape and murder of an Arakanese girl in late May, allegedly by three Muslims, led to a brutal revenge attack on ten Muslim pilgrims. Locals from both Rohingya and Arakanese communities complained that authorities failed to foresee and preempt the crisis, despite rising hostilities fanned by local nationalists and biased media coverage.

“Even with regard to the initial June 3 attack on Muslim travelers by an Arakan mob in Toungop, police and army soldiers witnessed the killings but did not intervene. A witness told Human Rights Watch that the authorities took action only to collect the dead bodies.”

As mass riots then engulfed the region and systematically became more organised, regional police and security forces remained indifferent. One witness was reportedly told by a police officer that they could not intervene because they had “not been given any order to take action”.

A 40-year-old Arakan man in Sittwe told HRW, “The government didn’t help us. We had no food, no shelter, and no security [when we fled], but we protected ourselves using sticks and knives.”

It was only after a state of emergency was declared on 10 June that security forces took action, by teaming up with locals to target the Rohingya in a wave of arbitrary violence, mass arrests and forced displacement.

“Burmese security forces failed to protect the Arakan and Rohingya from each other and then unleashed a campaign of violence and mass roundups against the Rohingya,” said Brad Adams, Asia director at Human Rights Watch.

“The government claims it is committed to ending ethnic strife and abuse, but recent events in Arakan State demonstrate that state-sponsored persecution and discrimination persist.”

More than 50,000 displaced Rohingya are estimated to be living in squalid, makeshift camps segregated from the Arakanese population, where foreign journalists and human rights researchers are denied access.

The report accuses local authorities of deliberately interfering with the distribution of humanitarian aid during the aftermath of the deadly clashes. International aid agencies have been forced to cut back their operations over security concerns, and ten aid workers were arrested in early July for dubious reasons.

The research also highlights the devastating role played by nationalists groups in fuelling distrust against the Rohingya community and international aid agencies through the distribution of incendiary leaflets. One pamphlet says that anyone working for the Rohingya will be considered a “traitor and thereby our enemy” and called on locals to attack UN agencies.

A number of regional monks associations have also instigated a campaign to boycott Rohingyas, which HRW says has exacerbated their ability to access food and basic services. Witnesses told the rights group that Burmese army soldiers who would previously go to the local market on their behalf to buy rice and other supplies would no longer do so.

“Most of the Arakan are now refusing to sell food to the Muslims,” said a 42-year old displaced Rohingya.

Analysts say the recent crisis is symptomatic of the government’s policy of discrimination against the stateless group, which was officially stripped of citizenship by former military dictator Ne Win in 1982. On Tuesday, Immigration Minister Khin Yi reiterated the government’s view that Rohingyas are “illegal Bengali immigrants” and cannot be considered Burmese citizens.

“The Burmese government needs to urgently amend its citizenship law to end official discrimination against the Rohingya,” Adams said. “President Thein Sein cannot credibly claim to be promoting human rights while calling for the expulsion of people because of their ethnicity and religion.”

The government has so far rejected calls for an inquiry into the violence, but recently granted access to UN Special Rapporteur for Human Rights in Burma, Tomas Quintana, who is visiting the region this week.