The country has been under emergency rule for over a year and a half, but as Bangladesh prepares for its elections in December, a nationwide crackdown has already started.

Opposition sources say the detainees are mostly grassroots activists, including leaders of the Awami league and Bangladesh nationalist party, who say they will boycott talks on organising an election later in the year.

In the last two weeks, the interim government says its detained at least 25,000 people, on charges of corruption.

Among them, the eldest son of Khaleda Zia, former prime minister.

Lawyers for Tareque Rahman said he has been tortured during custody, and that he may be permanently crippled as a result.

However Zia's son is one case among thousands, as Al Jazeera's Nicolas Haque reports from Dhaka.