My dismissal is the result of the president's remarks against me and my friends

Moncef Marzouki

He warned it heralded more action against opposition and human rights activists, promising to appeal against his dismissal.

'Treason'

In his speech, President Ben Ali said his critics were mercenaries involved in a smear campaign against Tunisia abroad.

The president said their actions "without patriotic or moral scruples, amount to treason against which we have to resort to the law if necessary".

A former director of the Tunisian League for Human Rights, Mr Marzouki has been a thorn in the side of the government for several years. In 1994, he unsuccessfully tried to challenge Mr Ben Ali in presidential elections.

Last month, Mr Marzouki had criticised the government for alleged human rights abuses and corruption during the first foreign trip allowed to him in years.

Despite introducing press freedoms and freeing some political prisoners, human rights groups have repeatedly criticised the government's treatment of its opponents.

Mr Ben Ali faces reproach at home and abroad for the 99.9% of the vote his party has consistently won in elections, most recently the presidential poll in October 1999.