BOUAZZA BEN BOUAZZA, Associated Press

TUNIS, Tunisia (AP) — Tunisia sank deeper into political crisis Thursday, as the ruling Islamist party rejected its own prime minister’s decision to replace the government after the assassination of a leftist politician led to a wave of angry protests.

The murder of Chokri Belaid, a 48-year-old secularist and a fierce critic of hardline Islamists as well as the more moderate ruling party, laid bare the challenges facing this nation of 10 million, whose revolution two years ago sparked the Arab Spring uprisings.

Because of its small, well-educated population, there were hopes Tunisia would have the easiest time transitioning from dictatorship to democracy. But instead Tunisia — a staunchly secular state under ex-dictator Zine El Abidine Ben Ali — is now a battleground pitting secularists, moderate Islamists, and hardline Islamists against one another.

The economy has struggled, power-sharing negotiations have stalled, and political violence is on the rise. The rejection of the prime minister’s move to create a government of technocrats to guide the country to elections also made clear that divisions exist between hardliners and moderates within the ruling party, Ennahda.

Police used tear gas Thursday to drive off the few dozen protesters who tried to demonstrate in front of the Interior Ministry, averting a repeat of the large rallies that swept the capital hours after Belaid’s assassination Wednesday.

But full-scale riots hit the southern mining city of Gafsa, where Belaid’s Popular Front coalition of leftist parties enjoys strong support. The state news agency TAP also reported clashes in cities across the country, with police resorting to tear gas and warning shots. In the northwest town of Boussalem, demonstrators set fire to a police station.

The tension could escalate Friday. Dramatic turnout is expected for Belaid’s funeral; coupled with a general strike called by the main labor union, the events raise the prospect of confrontations nationwide.

The police and army have been put on alert to prevent any outbreaks of violence and to “deal with any troublemakers” announced the presidential spokesman Adnan Mancer in a press conference late Thursday.

He added that police are questioning a possible suspect in the murder — a member of Belaid’s political party who was working as his chauffer and was witnessed speaking with one of the assailants before the politician was shot to death in his car outside his home Wednesday morning.

The latest events have raised fears Tunisia may not be an exception to the turmoil in the region, where several states are in a post-revolutionary phase.

The situation has yet to degenerate to the point of Egypt, the scene of regular street battles between police and protesters and a total breakdown of trust between the Islamist government and the opposition. Tunisia’s Islamists rule in coalition with two secular parties and must rely on consensus more than Egypt’s Muslim Brotherhood.

Ennahda was long repressed under the secular rule of Ben Ali, but after his overthrow in January 2011, the well-organized movement won subsequent elections. Overall, Ennahda is considered a moderate grouping. Hardline Islamists known as Salafis have come out against it.

Belaid’s death came as relations between the government and the opposition had deteriorated, with talks on a government reshuffle going nowhere. To make matters worse, critics such as Belaid accused the government of relying on hired thugs to attack meetings of the opposition.

To ease tensions, Prime Minister Hamadi Jebali announced late Wednesday he would dissolve the government and form a new one of nonpartisan technocrats to manage the country until elections, giving in to the longstanding opposition demand.

On Thursday, however, the party’s executive committee rejected the move and maintained that it was not going to toss away legitimacy it had gained in elections.

“The position of Ennahda is that the troika [the three-party ruling coalition] will continue to lead the country but it is open to a partial ministerial reshuffle,” party spokesman Abdallah Zouari told The Associated Press. That is the same position the party had before the assassination and subsequent protests.

A high-level member of the party who asked to remain anonymous because of the sensitivity of the subject said the party was already in talks with its coalition partners and the opposition to resolve the crisis. The party has also bolstered its position in the constitutional assembly by allying with three other small parties, giving it a comfortable two-thirds majority of the 217-seat body.

“With this increase, Ennahda and its allies have a comfortable majority to confront calls doubting our legitimacy in the assembly,” said Ziad Doulatli, a member of the party’s ruling council. Opposition parties had suspended their participation in the body after Wednesday’s assassination.

Opposition attacks on the governing coalition in the wake of the assassination may have gone too far, according to the Mancer, the presidential spokesman. He said some political figures were under investigation for inciting the army to deny the state’s legitimacy — without mentioning any names.

Belaid’s family and associates blame Ennahda for complicity in his killing, but have not offered proof, and other opposition figures have claimed there is a list of potential targets. Ennahda denies any involvement.

“It is the Ennahda and no one else that killed him,” said the slain politician’s father, Salah Belaid, at his home as mourners came to pay their respects. “He told me, ‘Father, they are targeting me’ … most of the time he wasn’t sleeping at his home.”

In an autopsy attended by the country’s chief prosecutor Wednesday night, the coroner removed three bullets from Belaid’s body as well as pieces of glass from the car window the gunmen shot him through.

Opposition parties had hailed Jebali’s attempt to form a new government as courageous. The year-old government has often been criticized for being unable to tackle the country’s problems, chief among them high unemployment and an economy battered by Europe’s financial crisis and too few tourists.

“It’s a recognition of the need to totally change the government which is incapable of running the country,” said Taieb Baccouche, secretary-general of the right-of-center Tunisia’s Call party, one of the main opposition parties. “There has to be immediate consultation between all the parties involved to avoid unilateral decisions.”

The country’s largest labor union, the General Union of Tunisian Workers, called for a general strike on Friday in a clear expression of their opposition to the Ennahda government. A threat to call a general strike in December was defused by negotiations.

As one of the most organized groups in society and with a left-wing leadership, the UGTT, as it is known, has long been a counterbalance to Ennahda’s formidable grass roots network. The last time it called a general strike, in 1978, riots erupted around the country.

Associated Press reporters Oleg Cetinic in Tunis and Paul Schemm in Rabat contributed to this report.