Myanmar's Aung San Suu Kyi has blamed "terrorists" for "a huge iceberg of misinformation" on the violence in Rakhine state, but made no mention of the nearly 125,000 Rohingya Muslims who have recently fled over the border to Bangladesh.

Key points: UN Security-General Antonio Guterres has urged the UN Security Council to press for restraint and calm

UN Security-General Antonio Guterres has urged the UN Security Council to press for restraint and calm Rohingya clashes with a military counter-offensive have killed at least 400 people

Rohingya clashes with a military counter-offensive have killed at least 400 people Myanmar has been laying landmines across a section of its border with Bangladesh

The leader of the Buddhist-majority country has come under pressure from countries with Muslim populations over the crisis, and United Nations secretary-general Antonio Guterres warned of the risk of ethnic cleansing and regional destabilisation.

In a rare letter expressing concern that the violence that has raged for nearly two weeks in the north-eastern state could spiral into a "humanitarian catastrophe", Mr Guterres urged the UN Security Council to press for restraint and calm.

In a statement issued by Ms Suu Kyi's office on Facebook, she said the Government had "already started defending all the people in Rakhine in the best way possible" and warned against misinformation that could mar relations with other countries.

She referred to tweets of images of killings posted by Turkey's Deputy Prime Minister that he later deleted because they were not from Myanmar.

"She said that kind of fake information which was inflicted on the Deputy Prime Minister was simply the tip of a huge iceberg of misinformation calculated to create a lot of problems between different countries and with the aim of promoting the interests of the terrorists," the social media statement said.

Sorry, this video has expired More than 100 Rohingyas were reportedly killed in a massacre last week.

More than 120,000 Rohingya have fled to Bangladesh

Energy spent blaming Suu Kyi for this crisis is wasted It feels strangely satisfying to blame Aung San Suu Kyi for the plight of the Rohingya, but it's misguided. If there's one person the world's ire should be focused on, it's General Min Aung Hlaing, the chief of Myanmar's military. And also the leader of the insurgent Arakan Rohingya Salvation Army, Ataullah Abu Jununi. Myanmar is not like Australia; the prime minister/president is not the commander-in-chief. Aung San Suu Kyi has no power over the military. There's been no sign Ms Suu Kyi has any great affection for the Rohingya, which unfortunately reflects the overwhelming view of her constituents. But don't forget, she was the one who arranged for UN heavy-hitter Kofi Annan to lead a commission that came up with recommendations to start addressing specific issues - the only real glimmer of hope for decades. That hope was cruelly crushed by the recent violence. Yes, she should speak up for the Rohingya and lead her people away from prejudice. But doing so would be political suicide, risking the very thing she struggled for all those lonely years under house arrest. It's fair to feel disappointed in Ms Suu Kyi, to wish she had the moral courage to do more; but energy spent blaming her for this crisis is energy wasted. -Analysis by South-East Asia correspondent Liam Cochrane

The latest violence in Rakhine state began 12 days ago when Rohingya insurgents attacked dozens of police posts and an army base.

The ensuing clashes and a military counter-offensive have killed at least 400 people and triggered the exodus of villagers to Bangladesh.

Ms Suu Kyi has been accused by Western critics of not speaking out for the minority that has long complained of persecution, and some have called for the Nobel Peace Prize she won in 1991 as a champion of democracy to be revoked.

Myanmar says its security forces are fighting a legitimate campaign against "terrorists" responsible for a string of attacks on police posts and the army since last October.

Myanmar officials blame Rohingya militants for the burning of homes and civilian deaths.

But rights monitors and Rohingya fleeing to neighbouring Bangladesh say the Myanmar army is trying to force them out with a campaign of arson and killings.

Hundreds more of exhausted Rohingya have been seen arriving on boats near the Bangladeshi border village of Shamlapur on Tuesday, suggesting the exodus was far from over.

More than 120,000 Rohingya have fled to Bangladesh due to the violence. ( AP: Bernat Armangue )

Myanmar lays landmines on its border

The new arrivals — many sick or wounded — have strained the resources of aid agencies and communities already helping hundreds of thousands of refugees from previous spasms of violence in Myanmar.

The International Organisation for Migration said humanitarian assistance needed to increase urgently and that it and partner agencies had an immediate funding gap of US$18 million (AU$22.5 million) over the next three months to boost lifesaving services for the new arrivals.

The latest estimate of the numbers that have crossed into Bangladesh, based on calculations by UN workers, is 123,600.

That takes to about 210,000 the number of Rohingya who have sought refuge in Bangladesh since last October, when Rohingya insurgents staged smaller attacks on security posts, triggering a major Myanmar army counter-offensive.

Myanmar has been laying landmines across a section of its border with Bangladesh for the past three days, two government sources in Dhaka said, adding that the purpose might have been to prevent the return of Rohingya Muslims fleeing violence.

Bangladesh will formally lodge a protest on Wednesday against the laying of land mines so close to the border, sources said.

Reuters