DHAKA - Bangladesh on Monday proposed joint military operations with Myanmar against Rohingyas fighting in Rakhine state, where thousands of villagers have fled fresh violence in recent days, an official said.

An upsurge in fighting in Rakhine, an impoverished state neighbouring Bangladesh, has been raging since Friday when Rohingya militants staged coordinated ambushes against Myanmar's security forces.

More than 100 people, including around 80 militants, have been confirmed killed in the fightback, which has seen thousands of Rohingya villagers fleeing for Bangladesh.

More than 3,000 Rohingya have arrived in Bangladesh from Myanmar, where the stateless Muslim minority faces persecution, in the past three days, the UN refugee agency said Monday.

Bangladesh has said there are thousands more Rohingya massed on its border with Myanmar, where it has stepped up patrols and pushed back hundreds of civilians who have tried to enter.

In a meeting with Myanmar's charge d'affaires in Dhaka, a top Bangladeshi foreign ministry official proposed joint military efforts against the militants along the border.

"We proposed that if Myanmar wished, the security forces of the two countries could conduct joint operations against the militants, any non-state actors or the Arakan Army along the Bangladesh-Myanmar border," a foreign ministry official said on condition of anonymity, as he was not permitted to speak to the media. The Arakan Rohingya Salvation Army (ARSA) is a militant group that says it is fighting to protect the Muslim minority from abuses by Myanmar security forces and the majority-Buddhist Rakhine community.

There was no comment from the Myanmar diplomat.

At the weekend, as violence in Rakhine worsened, Bangladesh's foreign minister summoned Myanmar's charge'd affaires in Dhaka to express "serious concern" at the possibility of a fresh refugee influx.

There are already some 400,000 Rohingya refugees in Bangladesh in squalid camps near its border with Myanmar. Bangladesh is waging a bloody crackdown on homegrown militancy and has vowed 'zero tolerance' towards violent extremism, domestic or otherwise, on its soil.

Dhaka has repeatedly asked Myanmar to take back the Rohingya refugees and address the root causes of problem "through a comprehensive and inclusive approach".

Despite decades of persecution, the Rohingya in Myanmar's western Rakhine state largely eschewed violence.

But in October ARSA, a small and previously unknown militant group, staged a series of well coordinated and deadly attacks on security forces.

Myanmar's military responded with a massive security crackdown. Some 87,000 new refugees flooded into Bangladesh bringing with them harrowing stories of murder, rape and burned villages.

The UN believes the army's response many amount to ethnic cleansing, allegations denied by the government of Aung San Suu Kyi and the army.

In recent months the day-to-day fighting died down, but civilians described being trapped between army "clearance operations" and an assassination campaign by the militants, who are murdering anyone suspected of collaboration.  Rohingya refugees in Bangladesh told Monday how they fled for their lives from Myanmar's army as the UN refugee agency said more than 3,000 had arrived in the past three days. The influx follows a fresh outbreak of fighting between Rohingya militants and Myanmar troops in Rakhine state, which borders Bangladesh.

Bangladesh has said there are thousands more Rohingya massed on its border with Myanmar, where the stateless minority face persecution.

Dhaka has responded by stepping up border controls and pushing back hundreds of Rohingya who try to enter, although some have still managed to evade the guards.

Those who have got through took refuge in the mostly makeshift camps in the coastal town of Cox's Bazar, where some 400,000 Rohingya are already living after fleeing previous bouts of violence in Rakhine.

Sona Mia said at least 800 had arrived at his Balukhali camp since Friday.

"Police said we can't let them stay or else we would be deported. We helped them enter through several points but are sending them to Kutupalong," said Mia, referring to another camp.

Authorities at the Chittagong Medical College Hospital said they were treating 17 Rohingya. One had died of gunshot wounds on Saturday.

Mohammad Ziabul, a 27-year-old farmer, fled for his life after Myanmar troops shot and killed his brother.

"We started running for cover when Myanmar army started firing indiscriminately on Friday," he said.

"Two bullets hit my body - one at my left hand and the other one at my head. I fell on the ground. My elder brother Dil Mahmud who was also hit by bullet, died on the spot."

He said around 1,000 Rohingya had fled his village alone to hide out in the forest.

The UN High Commissioner for Refugees (UNHCR) said many of the new arrivals are women and children.

"UNHCR and other UN Agency teams in registered camps estimated that more than 3,000 'newly arrived' individuals were seen in and around the camp," said UNHCR spokesman Joseph Tripura.

"Many of the new arrivals are women and children including some un-accompanied and/or separated children."

Abdur Rashid, another Rohingya farmer, described walking miles with his 10-year-old son to hospital in Bangladesh after the child was hit by a bullet in Myanmar.

"I left my five other children and my wife in Myanmar. I don't know what happened to them," he said.