Thousands rallied in Tunisia on Saturday after the main trade union called for a new government of "national salvation," as the prime minister promised the first democratic elections since independence.

Protesters in Tunis were also joined by dozens of members of the police force, discredited because of the bloody crackdown on protests against president Zine El Abidine Ben Ali that ultimately led to his ouster on 14 January .

Some of the officers briefly blocked a car carrying interim president Foued Mebazaa, the speaker of parliament, but it was later allowed to pass.

Security forces stepped up their patrols at key points in the city.

Mebazaa has promised a "total break" with the old regime and the government has unveiled key reforms such as the release of all political prisoners and the legalisation of political parties, but daily protests have continued.

Many in the country are angry about the inclusion of old regime figures like Prime Minister Mohammed Ghannouchi in the new government and want the break-up of the former ruling party, which has dominated Tunisia for decades.

There have been daily rallies in Tunis and other cities around Tunisia, which have passed off mostly peacefully and have drawn fewer people than the mass protests seen in the final days of Ben Ali's regime.

Ghannouchi, who has kept his post despite the revolt, vowed to quit politics after the north African country's first fair polls since independence from France in 1956, in comments broadcast on Friday.

"After the transition, I will retire from political life," said Ghannouchi, who has been prime minister since 1999. He also said that like many Tunisians he too was "afraid" under the Ben Ali regime.

"All undemocratic laws will be scrapped" during the transition to democracy, he added, mentioning in particular electoral, anti-terrorism and media laws.

He did not give a precise date for when elections would be held, although he has previously said there will be a vote within six months. Under the constitution elections should officially take place within two months.

"The prime minister is sticking to the same tone," said opposition leader Mustapha Ben Jaafar, head of the Democracy Forum for Labour and Liberty party, who had been appointed as health minister in the new government but pulled out.

"There is a willingness to exit the crisis but still a lack of comprehension of the depth of the rejection expressed by the population against every symbol that has a link or had a link with the old regime," Ben Jaafar told AFP.

"We're not in a normal situation, we're in a real revolution," he said, adding: "The country is waiting for a clean break as soon as possible."

The independent daily Le Quotidien said: "The street is still boiling over.... It's clear that transition to a truly democratic regime will not happen without a hitch."

Protesters "are determined to wipe out any trace of the old regime and its ideological instrument, the RCD" -- the ex-ruling Constitutional Democratic Rally party, it said.

Saturday's rallies come on the second day of a national mourning period put in place by the new authorities for the victims of the revolt against Ben Ali.

Officials say 78 people were killed during weeks of protest and they have been hailed by Tunisia's imams as "martyrs of the revolution".

Flags flew at half-mast and public television broadcast Quranic prayers.

The UGTT union, which played a key role in the protests, meanwhile rejected the government installed because it has kept in place some of the same people in key posts despite unveiling huge democratic reforms.

There is also still deep resentment in central Tunisia, where the protests began a month ago, over social and economic conditions there.

One protestor at a rally on Friday held up a sign reading "Our President" next to a photograph of Mohammed Bouazizi, the 26-year-old fruit vendor who inspired the uprising against Ben Ali by setting himself on fire last month.

The protests forced Ben Ali to flee to Saudi Arabia after 23 years in power.