Bangladesh has deployed secret police in the burgeoning refugee camps near its border with Myanmar, where Rohingya claiming to be members of a militant group say they have found fertile ground for recruitment.

Authorities in Bangladesh, which was already grappling with its own militancy problem before the latest mass influx of Rohingya refugees, have repeatedly said there are no extremists among the new arrivals.

But inside the camps are a number of self-proclaimed members of the Arakan Rohingya Salvation Army (ARSA), the group behind the August 25 attacks on police posts in Myanmar that sparked a military crackdown that the UN has likened to ethnic cleansing.

Capitalising on anger over the unrest that has forced half a million Rohingya Muslims to flee to squalid camps in Bangladesh, recruiters claim to have enlisted hundreds willing to fight back in Myanmar, where the minority faced decades of persecution.

Those allegations are hard to verify. But authorities in Bangladesh have stepped up surveillance of the border area in recent weeks.

Mohammad Halim, who says he is a recruiter for ARSA, told AFP that volunteers were trained in combat, military tactics and the use of weapons — but he complained that they were unarmed.

“All that training seems to be vain, because we don't have weapons,” Halim said in a steamy tent in Cox's Bazar, using a pseudonym to protect his identity.

“If we had arms, we'd go back to Myanmar to fight... we would drive away the military and take back our land,” he told AFP.

Waiting for orders

The ARSA says it launched the August assault — and a previous attack in October 2016 — to fight back after decades of suffocating restrictions on Rohingya Muslims in Buddhist-dominated Myanmar, which denies them citizenship and free movement.

But the violence unleashed by the ARSA attacks has resulted in a massive exodus of the minority from their homes in Rakhine state.

ARSA, branded a terrorist organisation in Myanmar, is fronted by Ata Ullah, who is believed to have been born to a Rohingya family in Pakistan, and to have lived in Saudi Arabia.

Rohingya leaders have long rejected attempts by outside militants to radicalise the population.

But observers say increasingly oppressive restrictions imposed since communal violence between Muslims and Rakhine Buddhists in 2012 have allowed support for militancy to take root.

Security experts warn that radicalisation among the Rohingya would have far-reaching consequences, especially if global extremist groups tap ethnic rivalry in Myanmar's Rakhine state and anger in the refugee camps in Bangladesh.

Refugees fleeing the latest violence -— including sizeable Hindu and Buddhist minorities — have alleged atrocities by all sides, including mass killings and rapes.

ARSA has effectively gone underground in recent weeks, said Jahangir Alam, a newly arrived refugee who claimed he took part in the militant ambush on security forces last October.

Rohingya fighters were told to await orders and weapons, Alam said, but some in the camps were eager to avenge the slaughter of friends and family.

“We said we wanted to go back to our country. Nowhere else. We left our land and homes in Myanmar,” the muscular Rohingya youth told AFP, also using an alias. “We don't have anything here.”

His testimony, and that of other Rohingya men interviewed by AFP claiming to be militants, is difficult to confirm, although they had detailed knowledge of weapons, training methods and tactics used by the insurgents.

S.M Moniruzzaman, the regional police chief overseeing the refugee camps, rejected any suggestion that Rohingya militants were operating in Bangladesh.

“With confidence and determination, I can say there is no way ARSA... is harbouring militants in Bangladesh,” the Chittagong police chief told AFP, referring to the Rohingya insurgency.

The new Rohingya influx are “under surveillance”, Moniruzzaman added, with plain clothes police and “reliable sources” patrolling the camps.

The army has taken over aid distribution in camps — a move experts said could double as a security precaution.

“Definitely they must have that in the back of their mind,” said Abdur Rob, head of the political science department at Dhaka's North South University.

Bangladesh is already waging its own war on Islamist militants. In recent years, homegrown radicals have butchered secular bloggers and high-profile secularists.

An attack on a Dhaka cafe left 22 dead last year, mostly foreigners, and Home Minister Asaduzzaman Khan told AFP this week that Bangladesh had zero tolerance for militancy.

Security experts say there are valid concerns about Rohingya militants in Bangladesh, particularly if foreign extremist networks seek to exploit the crisis by arming and radicalising Muslims.

“The Rohingya insurgency will not be immune to that,” Bangladeshi militancy expert Shahab Enam Khan told AFP.

"This will have regional repercussions, and that includes Bangladesh."