The Rohingya largely averred violence despite years of suffocating restrictions and persecution. That dramatically changed last October when a nascent Rohingya militant group launched surprise attacks on border posts.

Myanmar’s military reacted with a violent “clearance operation” to sweep out the militants. The UN has said that crackdown may have amounted to ethnic cleansing.

Despite the sweeps, violence continued as remote villages were hit by near-daily killings of perceived state collaborators attributed to operatives of the Arakan Rohingya Solidarity Army (ARSA).

The militants struck again on a large scale on Friday, with scores attacking about 30 police posts in predawn raids, killing at least a dozen security forces using knives, home-made explosives and some guns.

This time the security response has led to more than 100 people, including some 80 militants, being confirmed killed and prodded thousands of Rohingya civilians to dash for Bangladesh. But the country, which already hosts tens of thousands of refugees from the Muslim minority in the Cox’s Bazar area, has refused entry to any more.

Those unable to sneak in are stranded along the “zero line” border zone, where Bangladeshi officials have noticed a conspicuous absence of men among the civilians crowding the check posts.

“We asked them what happened to their men. They said they all stayed back to fight,” a Border Guard Bangladesh (BGB) commander said, speaking on condition of anonymity.

At the border, Rohingya elder Shah Alam, a community leader from Rakhine state, said 30 young men from three villages in his district joined the ARSA “for our freedom”.

“Do they have any other choice? They chose to fight and die rather than be slaughtered like sheep,” he said.

The previously unknown militant group has claimed responsibility for the attacks in October and more recent strikes against Myanmar’s security forces, urging fellow Rohingya to join the fight.

Myanmar’s Aung San Suu Kyi has accused the group of atrocities including using child soldiers, allegations the militants deny.

The government department directly run by Suu Kyi – the State Counsellor’s Office – has classified the ARSA as “terrorists” and released a series of statements and grim pictures of civilians allegedly shot dead by militants.

But ARSA’s rallying cry is being answered in Rohingya camps across Bangladesh, despite some doubts over whether their rag-tag units – seemingly mainly armed with knives and home-made weapons – can defeat Myanmar troops.

Many of the displaced Rohingya said they barely escaped with their lives. They described Buddhist mobs and security forces shooting unarmed civilians and burning down homes, an abuse repeatedly documented in Rakhine since the escalation in conflict. For many, it was the final straw.

“Young people are fed up,” said one prominent Rohingya activist in Bangladesh who asked to remain anonymous. “They grew up witnessing humiliation and persecution, so the current consensus among the Rohingya community is unless you fight, they’re not going to give us any of our rights.”

Outside a camp in Cox’s Bazar two young Rohingya men were anxious to join the fight, describing it as “farj” – a religious duty – to join the “freedom fighters” in Rakhine.

“We don’t have any options. Our backs are on the wall. Even the teenagers in our villagers have joined the fight,” one of the men said, vowing “to cross the border on the first chance”.

Just one of Hafeza Khatun’s three sons crossed with her into Bangladesh last month, the older two staying back to fight. But her youngest joined them a week later at his mother’s blessing, returning to battle Myanmar’s security forces “who would kill us anyway” without resistance, she said.

“They are fighting for our rights. I sent my sons to fight for independence. I sacrificed them for Arakan,” she said.