The UN independent investigator into human rights in Myanmar has called for stronger international pressure to be exerted on Myanmar's military commanders after being barred from visiting the country for the rest of her tenure.

Key points: Yanghee Lee had planned to use her visit to find out procedures for the return of refugees

Yanghee Lee had planned to use her visit to find out procedures for the return of refugees She wanted to investigate increased fighting in Myanmar's Kachin and northern Shan areas

She wanted to investigate increased fighting in Myanmar's Kachin and northern Shan areas Countries including US and human groups are advocating targeted sanctions on the military

Yanghee Lee, UN special rapporteur, had been due to visit in January to assess human rights across Myanmar, including alleged abuses against Rohingya Muslims in Rakhine State.

But Myanmar had told her she was no longer welcome, she said, adding in a statement that this suggested "there must be something terribly awful happening" in the country.

"From what I see right now I'm not sure if they are feeling pressured," she said.

"I'm not sure if there is the right kind of pressure placed on the military commanders and the generals."

She said it was alarming that Myanmar was strongly supported by China, which has a veto at the UN's top table in New York.

Other countries including the United States and human groups were advocating targeted sanctions on the military, Ms Lee said.

"It has to work. And I'm sure the world has to find a way to make it work," she said.

"And I think the United Nations and its member states should really try to persuade China to really act towards the protection of human rights."

More than 650,000 Rohingya have fled into Bangladesh since August 25, when attacks by Muslim insurgents on the Myanmar security forces triggered a response by the army and Buddhist vigilantes.

Surveys of Rohingya refugees in Bangladesh by aid agency Medecins Sans Frontieres have shown at least 6,700 Rohingya were killed in Rakhine state in the month after violence flared up, MSF said last week.

The UN High Commissioner for Human Rights Zeid Ra'ad al-Hussein has called the violence "a textbook example of ethnic cleansing" and said he would not be surprised if a court eventually ruled that genocide had taken place.

Sorry, this video has expired Footage shows bodies and burning in Myanmar's 'ethnic cleansing' of Rohingya Muslims

Lee 'puzzled and disappointed' in change of decision

Ms Lee had planned to use her visit to find out procedures for the return of Rohingya refugees, and to investigate increased fighting in the Kachin and northern Shan areas of Myanmar.

The Government has repeatedly denied any violations of human rights.

"They have said that they have nothing to hide, but their lack of cooperation with my mandate and the fact-finding mission suggests otherwise," Ms Lee said.

She said she was "puzzled and disappointed", since Myanmar's Ambassador in Geneva Htin Lynn had told the UN Human Rights Council only two weeks ago that it would continue to cooperate.

"Now I am being told that this decision to no longer cooperate with me is based on the statement I made after I visited the country in July," she said.

Mr Lynn did not respond to a request for comment. Neither Zaw Htay, spokesman for Myanmar's de facto leader Aung San Suu Kyi, nor Kyaw Moe Tun, a spokesman for the ministry of foreign affairs that Ms Suu Kyi heads, were immediately available.

Reuters