LUANDA (AFP) - Fourteen Angolan opposition activists on trial since mid-November threatened on Monday (Dec 7) to go on hunger strike over what they said was the slow pace of the hearings.

"Now we can look forward to being convicted knowing that this is unfair," 14 of the 17 activists on trial said in an open letter to President Jose Eduardo dos Santos.

The group of 17 - which included prominent rapper Luaty Beirao, students, journalists and even members of the military - was arrested on June 20 at a youth movement gathering to demand the departure of dos Santos, who has been in power since 1979.

They were picked up during a meeting of a book-reading club where one of the books on the line-up was about non-violent resistance to repressive regimes.

They risk jail terms of up to 12 years if found guilty of "rebellion and a coup attempt." All deny the charges.

Three of the accused did not sign the letter to dos Santos.

"If the interrogation phase does not end in the week of Dec 7 to 11 we will refuse to go to the proceedings and we will begin a collective hunger strike which will end when our demands are met," said the letter.

The trial, which was initially scheduled to last five days, entered its fourth week on Monday, and only 10 of the 17 accused have been heard.

"We have been the first witnesses to all your interference throughout the trial and now in particular, in the middle of the trial," the letter to dos Santos said.

"The orders (of your men) are to indefinitely prolong the interrogations." They also condemned the refusal by authorities to allow international observers at the trial.

Rights groups say activists in Africa's second-largest oil producer are being increasingly targeted by dos Santos' government.

Amnesty International said the activists should have not been arrested in the first place and described their detention as a "travesty of justice".