YANGON • Myanmar has said a visiting US official would not be allowed to go to a region where violence has triggered an exodus of more than 400,000 Rohingya Muslims.

The Rohingya fled from western Rakhine state to neighbouring Bangladesh to escape a military offensive that has been described by the United Nations as a "textbook example of ethnic cleansing", and raised questions about Myanmar's transition to civilian rule under the leadership of Nobel Peace laureate Aung San Suu Kyi.

US Deputy Assistant Secretary of State Patrick Murphy will voice Washington's concerns about the Rohingya and press for greater access to the conflict area for humanitarian workers, the State Department said.

Myanmar officials said he will meet government leaders in the capital, Naypyitaw, and attend an address to the nation by Ms Suu Kyi on Tuesday. Mr Murphy will also visit Sittwe, the state capital, and meet the governor of Rakhine, the state government secretary Tin Maung Swe told Reuters last Friday.

But the north of the state where the conflict erupted on Aug 25 is off-limits. "Not allowed," Mr Tin Maung Swe said, when asked if Mr Murphy will be going to Maungdaw district, at the heart of the strife that began when Rohingya insurgents attacked police posts and an army camp, killing a dozen people.

While more than 400,000 refugees have poured across the border into Bangladesh, fears have also been growing of a humanitarian crisis on the Myanmar side, but access to the area for aid workers and reporters has been restricted.

Myanmar insisted on Friday that it was not barring aid workers but a government spokesman said the authorities on the ground might have concerns over security.

Rights monitors and fleeing Rohingya say the army and Rakhine Buddhist vigilantes have mounted a campaign of arson aimed at driving out the Muslim population.

Meanwhile, Bangladeshi Prime Minister Sheikh Hasina headed for the UN General Assembly yesterday to plead for global help coping with the Rohingya crisis as conditions worsen for the refugees.

She left a day after Dhaka summoned the Myanmar charge d'affaires to protest against alleged violations of its airspace by Myanmar drones and helicopter. The Bangladesh Foreign Ministry has warned that the three violations between Sept 10 and 14 could lead to "unwarranted consequences".

Mr Zaw Htay, the Myanmar government spokesman, said any information that Bangladesh provided would be checked. "At this time, our two countries are facing the refugee crisis. We need to collaborate with good understanding."

REUTERS, AGENCE FRANCE-PRESSE