By Jared Ferrie
YANGON, Jan 24 (Reuters) - Medical charity Medecins Sans Frontieres said on Friday it had treated 22 people in Myanmar's western Rakhine state who had apparently been wounded last week around the time of a reported massacre of Rohingya Muslims. The government has denied such an incident occurred.
The United Nations and human rights groups have said that at least 40 Rohingya were killed by security forces and ethnic Rakhine Buddhist civilians in mid-January in a restricted area of the conflict-ridden western state.
The United States said it was "deeply disturbed" by the reports and called on the government to launch an "immediate, credible, and independent investigation."
On Friday, government spokesman Ye Htut denied there had been any mass killing, in line with statements over the past week. But information provided by Medecins Sans Frontieres/Doctors Without Borders (MSF) further eroded the position of the government, which is facing international pressure to conduct an investigation.
"MSF has treated at least 22 patients, including several wounded, that are believed to be victims of the violence that erupted in Du Char Yar Tan village in southern Maungdaw township on Jan. 14," said Peter-Paul de Groote, the charity's head in Myanmar.
The organization, which runs a nearby clinic, said most victims had suffered knife wounds, while one was shot and three were beaten, one severely. MSF said it was concerned that more victims could need medical treatment and urged the government to allow access to the area.
Incidents in Maungdaw township and other parts of Rakhine state are difficult to verify independently as those places are off limits to journalists and the government strictly controls access by international aid groups.
If confirmed, the massacre would take to at least 277 the number of people killed in religious conflict across Myanmar since June 2012. More than 140,000 people have been displaced.
On Friday, the United States embassy urged senior Myanmar officials "to speak out publicly on the importance of respect and tolerance and to avoid speculating on the details of what took place". It also called on the government to conduct an impartial investigation with the United Nations.
"We are particularly disturbed by reports that some of the deaths and injuries may have resulted from security forces' use of excessive force," a U.S. embassy official told Reuters.
In Washington, D.C., State Department spokeswoman Marie Harf said the United States was "deeply disturbed" by the reports that at least 40 people had been killed and that policeman had disappeared.
"We reiterate our call for the government of Burma to launch an immediate, credible, and independent investigation into the violence and hold accountable those responsible," she said.
On Thursday, UN High Commissioner for Human Rights Navi Pillay said she had received credible reports that at least 40 Rohingya were killed by police and Rakhine residents in violence sparked by the murder of a police officer.
The UN had shared the information with the government, she said.
"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," she said in a statement.
Government spokesman Ye Htut insisted the police officer was the only person killed and said the U.N. statement would increase tension in the area.
"It will just fuel suspicions and concerns in Rakhine state and also erode local people's trust in the U.N. agencies," he said.
Most of the victims were Muslims and the most deadly incidents happened in Rakhine state, where about a million Rohingya live under apartheid-like conditions, denied citizenship, with their movements tightly restricted and little access to health care, jobs or education.
Bangkok-based rights group Fortify Rights said on Thursday that it had spoken to witnesses and other sources who confirmed the massacre, which would be the deadliest incident in Rakhine state since October 2012, when ethnic Rakhine Buddhists fought minority Rohingya Muslims.
Ye Htut urged those who fled the village to return and cooperate with authorities investigating the officer's death.
"The police force is giving protection to the people left in the village," he said. (Reporting by Jared Ferrie; Additional reporting by David Brunnstrom; Editing by Alan Raybould, Clarence Fernandez, Toni Reinhold)