Dhaka: The first prosecution witness of Bangladesh's International Crimes Tribunal on Wednesday testified against a top suspect of 1971 war crimes who was indicted two months ago on 20 charges of "crimes against humanity" during the Liberation War.

Court officials said a 1971 freedom fighters' commander Mahbubul Alam Hawladar appeared as the first witness since the Tribunal was constituted in March last year to try the Bengali-speaking perpetrators of 1971 war crimes.

He testified against fundamentalist Jamaat-e-Islami leader Delwar Hossain Sayeedi, who is the first indicted accused of the tribunal.

"Hawladar's deposition is underway and so far he narrated the background of Sayeedi's engagement with the Pakistani troops and their auxiliary and supporting forces", a prosecution lawyer told.

The prosecution last month submitted a 90-page statement against Sayeedi before the three-judge tribunal headed by High Court judge Nizamul Haque.

Chief prosecutor Ghulam Arieff Tipu and senior prosecutor Syed Rezaur Rahman read out statement and brought the charges including genocide, rape, murder, arson and looting.

Bangladesh in March last year constituted the high-powered three-member tribunal along with a special investigation agency and a prosecution cell in line with the election pledges of Prime Minister Sheikh Hasina's ruling Awami League to expose war criminals to justice.

Five of the seven high-profile war crime suspects detained so far to face the trial belonged to Jamaat-e-Islami, while the rest two were of now main opposition Bangladesh nationalist Party (BNP) of ex-Prime Minister Khaleda Zia.

The other Jamaat leaders are party chief Motiur Rahman Nizami, Secretary General Ali Ahsan Mohammad Mujahid and assistant secretaries general Muhammad Kamaruzzaman and Abdul Quader Molla.

The two BNP leaders are Salahuddin Qader Chowdhury MP and former minister Abdul Alim.

If convicted the accused could face the highest death penalty and the lowest 10 years of imprisonment for crimes like mass killings, murders, arsons and rapes but under the International Crimes Tribunal Act the convicts could file appeals before the apex Appellate Division of the Supreme Court alone.