Hammami wants his colleagues freed as well

The head of Tunisia's banned Communist Workers' Party says he will continue his political activity despite the threat of returning to jail.

Hamma Hammami was released from jail on Wednesday on health grounds just two days after losing his appeal against a three-year prison sentence.

He was accused of belonging to an illegal organisation and inciting rebellion.

President Zine al-Abidine Ben Ali keeps a tight reign on his country and routinely wins elections with 99.9% of the vote.

In May, he won a referendum changing the constitution so he could stand for a fourth term as president.

Hunger strike

Human rights groups led a vigorous campaign for Mr Hammami's release, which included a 38-day hunger strike by his wife.

He told the BBC's Network Africa programme that he had been kept in "inhumane" conditions.

The Tunisian authorities use arbitrary decisions to play with the freedom of Tunisians

Amnesty International

Because his release was conditional, "the authorities can send me back to jail if I commit any other political offences," he said.

But he said that he was not worried by this threat.

"I will carry on my political activities... If need be, I am ready to go to jail," he said.

Another member of the Communist party, Samir Tamallah, was also released on Wednesday but two more remain in custody.

Mr Hammami said he would campaign for the release of his colleagues.

No change

His health problems were caused by his treament in prison, he said.

"I spent five months in a cell with two other inmates and there wasn't a single window in the cell," he said.

Human rights group Amnesty International estimates that there are about 1,000 political prisoners in Tunisia.

While welcoming Mr Hammami's release, Amnesty said it did not signal a change of attitude by the government.

"The Tunisian authorities use arbitrary decisions to play with the freedom of Tunisians, which alternate between arrests and the release" of prisoners, the group said.