Tunis, Jan 19 (Agencies): Three ministers resigned from the Tunisia's unity government on Tuesday as protesters vented their anger at the new leadership just days after the ouster of the Arab state's strongman.

The ministers, representing Tunisia's main trade union, announced their withdrawal after the union refused to recognise an administration that contains eight ministers from President Zine El Abidine Ben Ali's dishonoured regime.

"We are resigning from the government after a call from our union," said Houssine Dimassi, training and employment minister in the transitional unity government unveiled only on Monday.

Dimassi said the two other ministers resigning were Abdeljelil Bedoui, a minister working in the prime minister's office, and Anouar Ben Gueddour, a junior transport minister.

Their UGTT labour union held an extraordinary meeting near Tunis earlier on Tuesday at which it decided not to recognise the new government.

The resignations concided with the return to Tunisia of opposition figure Moncef Marzouki, ending years of exile in Paris.

Anger against the new government line-up brought thousands of protesters onto the streets of Tunis and several other cities on Tuesday.

Riot police fired tear gas to break up a rally in Tunis led by key Islamist leader Sadok Chourou, who was imprisoned for 20 years under the old regime.

"The new government does not represent the people and has to fall," said Chourou, 63, ex-leader of the banned Ennahdha (Awakening) movement.

Police also broke up another rally in Tunis amid growing opposition to the government line-up. All public assemblies are officially banned under the rules of a state of emergency declared shortly before disgraced president Ben Ali resigned and fled on Friday.