By Alastair Lawson-Tancred BBC correspondent in Dhaka

A Bangladeshi opposition politician has become confused, stressed and has lost weight since he was arrested by the army and sent to prison, family members say.

Saber Hossain Chowdhury is one of the most high profile of about 5,000 people who have been arrested by troops since they were asked by the government to help restore law and order.

He was confused as to what the various charges were. He didn't really seem to know what they were...

Sadeq Chowdhury

He now faces a series of serious criminal charges, including the attempted murder of the Bangladeshi prime minister, Khaleda Zia, when she led the opposition last year.

Saber Hossain Chowdhury's supporters say it is ludicrous that he should have been arrested as part of the government's campaign to eradicate violent crime.

They say he is a political rather than a criminal prisoner and the government is using the army to silence its political opponents.

Stressed

Mr Chowdhury's brother, Sadeq, is the first family member to have been allowed to visit him in prison since his arrest over two weeks ago.

He told the BBC: "He's under a lot of stress. He appeared quite pale and seemed to have lost a lot of weight.

There have been problems with law and order

"He was confused as to what the various charges were. He didn't really seem to know what they were, didn't know who was representing him.

"Also the fact that he hasn't had access to lawyers, as yet, to visit him to discuss with him the various charges."

The human rights group, Amnesty International, has expressed serious concerns about Mr Chowdhury's arrest, along with other members of the opposition.

They are also worried about the number of people who have died in military custody since the army deployment, known as Operation Clean Heart, began.

Concerns about the army's new role have also been expressed by the American State Department.

But the government says that troops have significantly lowered violent crime and made Bangladesh a safer place.