Tunisia's ruling moderate Islamist Ennahda party has rejected Prime Minister Hamdi Jebali's decision to dissolve the government to make way for a caretaker administration in the wake of the murder of an opposition leader.

Jebali's move, which was welcomed by centrist Nida Tunis party, came after the first assassination of a political leader in post-revolutionary Tunisia - two years after the Arab Spring. The 48-year-old leftist secular leader Chokri Belaid, a harsh critic of Ennahda, was shot point-blank four times outside his home in Tunis. His assassination led to claims of government negligence and complicity.

Hundreds of demonstrators flocked to the interior ministry building in Tunis to chant anti-government slogans. There were sporadic episodes of violence as demonstrators clashed with police in scenes reminiscent of the final days of dictator Zine al-Abidine Ben Ali. Angry mourners lined the streets where the ambulance containing Belaid's body passed and at least one policeman died in fighting.

Jebali responded to the assassination of Belaid by proposing a new government of technocrats to lead to country to general elections. He said the new ministers "would not belong to any party and [the caretaker government's] task would be limited to organising elections as soon as possible with a neutral administration".

But the vice-president of Ennahda dismissed Jebali's proposal.

"The prime minister did not ask the opinion of his party," said Abdelhamid Jelassi,. "We in Ennahda believe Tunisia needs a political government now. We will continue discussions with others parties about forming a coalition government."

Belaid's wife, Basma, said that her husband "died for the country".

"He died for democracy," she added. "He was threatened all the time."

Belaid accused Ennahda of tolerating the ultraconservatives, or Salafists, who have defaced mausoleums and art exhibitions while hiding behind the mask of liberalism and democratic values. His killing came as the government was in talks with the opposition for a cabinet reshuffle to expand the ruling coalition.