The top U.N. human rights official denounced Myanmar for conducting a “cruel military operation” against Rohingya Muslims in Rakhine, branding it “a textbook example of ethnic cleansing”.

Pressure mounted on Myanmar on Tuesday to end violence that has sent more than 300,000 Muslims fleeing to Bangladesh, with the United States calling for the protection of civilians and Bangladesh seeking international help to handle the crisis.

The government of Buddhist-majority Myanmar says its security forces are fighting “terrorists” behind the latest wave of attacks, which began on Aug. 25, and they are doing all they can to avoid harming civilians.

The top U.N. human rights official denounced Myanmar on Monday for conducting a “cruel military operation” against Rohingya Muslims in the west Myanmar state of Rakhine, branding it “a textbook example of ethnic cleansing”.

The United States said the violent displacement of Rohingya Muslims showed Myanmar’s security forces were not protecting civilians. Washington has been a staunch supporter of Myanmar's transition from decades of harsh military rule that is being led by Nobel peace laureate Aung San Suu Kyi.

“We call on Burmese security authorities to respect the rule of law, stop the violence, and end the displacement of civilians from all communities,” the White House said in a statement.

Myanmar government spokesmen were not immediately available for comment but a spokesman for Ms. Suu Kyi said shortly before the U.S. statement was issued that Myanmar was also concerned about the suffering. Its forces were carrying out their legitimate duty to restore order in response to acts of extremism, he said.

“The government of Myanmar fully shares the concern of the international community regarding the displacement and suffering of all communities affected by the latest escalation of violence ignited by the acts of terrorism,” the spokesman, Zaw Htay, said in a statement.

Myanmars government regards the approximately 1 million Rohingya as illegal migrants from neighbouring Bangladesh and denies them citizenship, even though many Rohingya families have lived there for generations.

Insurgent attacks

Attacks by a Rohingya insurgent group, the Arakan Rohingya Salvation Army (ARSA), on police posts and an army base in the north of Rakhine State on Aug. 25 provoked the military counter-offensive that refugees say is aimed at pushing Rohingya out of the country.

A similar but smaller wave of attacks by the same insurgents last October also led to what critics said was a heavy-handed response by the security forces that sent 87,000 Rohingya fleeing to Bangladesh.

Myanmar rebuffed on Sunday a ceasefire declared by ARSA to enable the delivery of aid to thousands of displaced and hungry people in the north of Rakhine State, declaring simply that it did not negotiate with terrorists.

Bangladesh is seeking help as it struggles to cope with the influx of more than 300,000 Rohingya since the latest violence began, who have joined more than 400,000 others already there.

The Bangladeshi parliament passed a resolution on Monday urging the international community to mount pressure on Myanmar to resolve the crisis.

The Bangladeshi Prime Minister, Sheikh Hasina, is due to take diplomats to the border later on Tuesday to show them the dire situation her country faces.

Bangladesh is seeking international support for a plan to relocate Rohingya to a remote Bay of Bengal island that critics say is flood-prone and unliveable.