By Farhana Haider BBC News, South Asia reporter

Authorities say some people are killed in crossfire in police shootouts

A UN special envoy has accused the Bangladeshi security forces of using murder as a means of law enforcement.

The UN's envoy on extra-judicial killings said that the authorities had not responded to his request for information on 27 deaths.

Philip Alston said the Bangladeshi authorities had attributed the deaths to crossfire in police shootouts.

Government officials have disputed the figures and say any criminals killed opened fire first on security forces.

Mr Alston said the pattern of deaths suggested that they were in fact staged extra-judicial executions.

'Deeply disturbing'

Human rights groups have in the past accused the elite security forces of being responsible for extra-judicial killings but it is rare for the UN to directly accuse the government of, in effect, turning a blind eye to the incidents.

He called Bangladeshi government's apparent indifference to the allegations deeply disturbing.

Human rights groups have accused the elite crime force - the Rapid Action Battalion - of killing more than 400 people since it was set up in 2004 amid concerns about rising crime in the country.

Mr Alston also said that the state of emergency, declared by the interim government in January, could not justify any violations of the right to life.