A United Nations human rights expert has called for an urgent independent investigation into recent sectarian violence in Burma’s Rakhine state that left at least 78 dead and tens of thousands homeless.

Tomas Ojea Quintana ended a week-long visit to Myanmar on Saturday saying he had witnessed “widespread suffering” in the western state. He said he recorded allegations of serious violations by authorities including killings, torture, arbitrary arrest and excessive use of force.

He said it was a “matter of urgency” to set up an independent and credible investigation into the allegations of rights abuses.

He also called for the release of all political prisoners, saying that a democratic transition in the country cannot move forward without those steps.