Malaysian prime minister Najib Razak led a protest rally on Sunday against what he called a “genocide” of Myanmar’s Muslim Rohingya minority, as he urged Asian neighbours and the world to step up the pressure to stop the violence.

Najib said the rally at a stadium in Kuala Lumpur would send a strong message to Aung San Suu Kyi’s government that “enough is enough”.

“UN please do something. The world cannot sit by and watch genocide taking place,” Najib said to loud cheers from thousands of Muslims, including Rohingya refugees. “The world cannot say it is not our problem. It is our problem,” he said.

The plight of Rohingya in predominantly Buddhist Myanmar has galvanised Muslims in south-east Asia and beyond. Denied citizenship although they have lived in Myanmar for generations, Rohingya have faced persecution that exploded in intercommunal violence in Rakhine state in 2012. Hundreds were killed and more than 100,000 were forced into squalid camps.

The violence has again flared up as Myanmar’s military launched attacks on Rohingya villages following deadly strikes by unknown assailants on police posts along the border with Bangladesh in October.

Malaysian prime minister Najib Razak addresses Rohingya Muslim refugees in Kuala Lumpur. Photograph: Manan Vatsyayana/AFP/Getty Images

The top US diplomat for east Asia, Daniel Russel, said the escalation of violence risked inciting jihadi extremism in Myanmar and Bangladesh and called on neighbouring countries, including Malaysia and Indonesia, to resist the urge to stage protests that could further stir religious passions.

Najib said the persecution of the Rohingya was an insult on Islam. He said he had asked Indonesian president Joko Widodo to stage a similar rally in Jakarta to put pressure on Myanmar, because he said the charter of the 10-member Association of South-east Asian Nations (Asean), to which all three countries belong, ensured the protection of human rights.

The Malaysian government-led protest marks a departure from the long-standing policy of non-interference by Asean members in each other’s affairs.

“I will not close my eyes and shut my mouth. We must defend them [Rohingya] not just because they are of the same faith but they are humans, their lives have values,” Najib said.

Some critics accuse Najib, who is grappling with a financial scandal, of using the rally to win the support of his country’s Muslim Malays before general elections which are due in 2018 but may be called earlier.

In a strongly worded statement on Saturday, Malaysia’s foreign ministry said there were 56,000 Rohingya refugees in Malaysia. It said it had an obligation to halt the “ethnic cleansing” of the Rohingya and ensure security and stability in the region.

Malaysia has also summoned the Myanmar ambassador over the issue, and withdrew from two scheduled friendly football matches against Myanmar this month. Hundreds also protested outside the Myanmar embassy last week.