Tunisia jails dissident reporter Taoufik Ben Brik

Officials have denied inventing charges against Taoufik Ben Brik

A prominent critic of Tunisian leader President Zine El Abidine Ben Ali has been jailed for six months after a trial criticised by rights groups.

Taoufik Ben Brik was convicted of assaulting a woman in public.

But he claimed he had been framed and Amnesty International has described him as a "prisoner of conscience" and condemned his sentence.

President Ben Ali, in power for 22 years, tolerates little dissent, though officials deny inventing the charges.

The 49-year-old journalist was said to be ill and in need of medical treatment after his arrest in October.

As well as criticism from rights groups and media organisations, the French government also expressed concern over his arrest.

French Foreign Minister Bernard Kouchner urged his release so he could receive treatment.

But according to Reuters news agency, Mr Ben Ali responded in a speech earlier this month by attacking "foreign interference" in Tunisia's internal affairs.

"This is a very disappointing outcome", said Malcolm Smart, Middle East and North Director at Amnesty International.

"Taoufik Ben Brik should not have been prosecuted, let alone convicted and sentenced to a prison term.

"Taoufik Ben Brik has been convicted on politically-motivated charges for exercising his right to freedom of expression."

Amnesty says the journalist's lawyers have been prevented from visiting him since 19 November.

The group says he was not taken to court to hear the sentence, which was handed to him in writing.