A Malaysian aid ship arrived in Bangladesh on Monday carrying aid for hundreds of thousands of Rohingya Muslims who have fled from Myanmar, many citing abuses by the Myanmar security forces.

Nearly 70,000 Rohingya have fled from Buddhist-majority Myanmar's Rakhine State to Bangladesh to escape a crackdown launched after nine policemen were killed in attacks on border posts on Oct. 9 that Myanmar blamed on Rohingya militants.

The U.N. human rights office said in a report this month Myanmar's security forces had committed mass killings and gang rapes of Rohingya Muslims and burned their villages.

Myanmar has denied almost all allegations of human rights abuses, and says a lawful counterinsurgency campaign has been under way since the October attacks on the security posts.

The violence has dismayed and outraged some of Myanmar's neighbours with mostly Muslim Malaysia being particularly vociferous in its criticism.

It has supported Muslim groups and aid organisations to arrange a shipment of more than 2,000 tonnes of aid for Rohingyas.

The ship's first stop was in the Myanmar port city of Yangon, last week, where it unloaded 500 tonnes of supplies.

A representative of the mission on the ship said it would unload about 2,000 tonnes of food and emergency supplies in Bangladesh, though staff were not being allowed access.

"We are not allowed to get off the ship or to visit the camps,” said the aid representative, who declined to be identified.

The 70,000 new arrivals joined more than 200,000 Rohingya already in Bangladesh, many living in camps, who fled earlier crackdowns in Myanmar.

A Bangladesh government official said the ship was on its way to the Chittagong port after anchoring off the coastal town of Teknaf, near the Myanmar border, and arrangements were being made to unload its cargo.

But Ali Hossain, chief administrator of the coastal district of Cox's Bazar, which borders Myanmar, told Reuters he had not received clearance to let anyone off the ship.

A port official in Chittagong said a ceremony would be held on Tuesday with a senior foreign ministry official and Malaysia's ambassador in attending to receive the shipment.

U.N. officials working with refugees in Bangladesh have told Reuters the death toll in the Myanmar security sweep could be more than 1,000.

Rohingya have faced discrimination in Myanmar for generations. They are not classified as a distinct group under Myanmar's citizenship laws and are regarded instead as illegal immigrants from Bangladesh, entitled only to limited rights.

About 1.1 million Rohingya live in apartheid-like conditions in northwestern Myanmar.

Bangladesh says the Rohingya have been living in Myanmar for generations and are not Bangladeshis, and it faces a huge burden looking after the refugees.