The Office of the United Nations High Commissioner for Human Rights expressed deep concern about the recent reports of violence in Myanmar's Rakhine state, including the killings of many civilians.
The agency in a news release said it had received "credible information" eight Rohingya Muslim men were attacked and killed Jan. 9 in Du Chee Yar Tan. It said four days later during a clash in the same village a police sergeant was captured and killed by the Rohingya villagers.
Later the same evening, at least 40 Rohingya Muslim men, women and children were killed by police and civilians.
"I deplore the loss of life in Du Chee Yar Tan and call on the authorities to carry out a full, prompt and impartial investigation and ensure that victims and their families receive justice," Navi Pillay, the agency's high commissioner for human rights, said.
She said her office is ready to assist in the investigation.
"By responding to these incidents quickly and decisively, the government has an opportunity to show transparency and accountability, which will strengthen democracy and the rule of law in Myanmar," Pillay said.
The Myanmar government denied the killings.
Myanmar's deputy minister of information, quoted by CNN, said news reports about the killings are "wholly and totally wrong."