YANGON • A United Nations official has urged Myanmar's de facto leader Aung San Suu Kyi to visit the northern Rakhine state, where the army is accused of carrying out a brutal crackdown on the Muslim Rohingya minority.

The Nobel Peace Prize winner has faced growing international criticism for not stopping the military's campaign, which has pushed more than 20,000 Rohingya over the border to Bangladesh, bringing tales of mass rape, murder and arson.

The crackdown was launched in response to deadly raids on police posts in October.

Malaysia has accused the army of "genocide" - charges Myanmar officials have vehemently denied.

Ms Suu Kyi has described the situation as "under control" and asked the international community to stop stoking the "fires of resentment".

In a statement released in New York on Thursday, UN special adviser on Myanmar Vijay Nambiar appealed directly to the peace icon to intervene.

"The adoption of a generally defensive rather than proactive approach to providing security to the local population, has caused frustration locally and disappointment internationally," he said.

"I also appeal to Daw Suu to visit Maungdaw and Buthidaung, and reassure the civilian population there that they will be protected," he added, referring to the locked-down area in Rakhine.

The bloodshed presents the biggest challenge to Ms Suu Kyi since her party won Myanmar's first democratic election in over 50 years last year.

It has galvanised Muslim nations around the region, with protesters decrying the latest crackdown as the culmination of years of discrimination and abuse suffered by the stateless Rohingya.

On Sunday, Malaysian Prime Minister Najib Razak taunted Ms Suu Kyi, whom the former junta kept under house arrest for almost 20 years, before a crowd of some 5,000 protesters in Kuala Lumpur.

"What's the use of Aung San Suu Kyi having a Nobel Prize?" he asked the protesters. "The world cannot sit and watch genocide taking place."

Activists say Buddhist-majority Myanmar's Rohingya are among the most persecuted in the world.

More than 120,000 have been trapped in squalid displacement camps since the last major outbreak of violence erupted in Rakhine in 2012.

In his rally speech, Mr Najib suggested that Asean must set aside its principle of non-interference to tackle regional issues such as the Rohingya repressions and migrations, especially when they pose questions about universal values.

"We want to remind Myanmar's government that the Asean charter also upholds basic human rights," he said in his speech.

More than 100,000 Rohingya live in poverty and face harassment as illegal migrants in Malaysia. Many others have fallen into the hands of human traffickers on their perilous journeys from Myanmar.

AGENCE FRANCE-PRESSE, REUTERS