DHAKA, August 12, 2008 (AFP) - Unlawful killings by Bangladesh's elite Rapid Action Battalion (RAB) and police have surged in recent months with the army-backed government playing a silent role, Human Rights Watch said Tuesday.

The New York-based global rights group said the RAB and police had killed at least 50 people in 'suspect circumstances' over the past two months after a national outcry had stemmed killings for more than a year.

'Despite overwhelming evidence of RAB and police responsibility for unlawful killings, the interim Bangladeshi government seems unwilling to address the problem,' said Brad Adams, Asia director of the group.

'Instead, Bangladesh?s security forces continue to get away with murder.'

Since its inception in 2004, the RAB has been accused of killing more than 540 people, mainly top crime suspects and outlawed Maoists.

The authorities do not dispute the deaths but say the killings occur when suspects resist arrest or are caught in crossfire.

But local rights groups and Human Rights Watch say evidence has shown that many killings are poorly disguised extrajudicial executions, often preceded by torture.

They accused the country's police of copying the RAB actions.

In the latest incidents, HRW accused security forces of the torture and killing of Moshiul Alam Sentu, a Bangladesh Nationalist Party student activist whose body was dumped near the southern city of Barisal.

'The body had two bullet wounds in the chest and another in the leg. Sentu?s neck was severely bruised and possibly broken, as was his left hand, indicating possible torture,' it said.

The RAB, however, said Sentu was a wanted criminal and was killed in crossfire as its officers were attacked by his associates.