TUNIS, Tunisia — Shaken by the assassination of a prominent leftist opposition leader that unleashed major protests, Tunisia’s prime minister announced Wednesday that he would form a new government of technocrats to guide the country to elections “as soon as possible.”

The decision by Prime Minister Hamadi Jebali was a concession to the opposition, which has long demanded a reshuffle of the Islamist dominated government. It was made hours after the first assassination of a political leader in post-revolutionary Tunisia.

The killing of 48-year-old Chokri Belaid, a secularist and critic of the ruling Islamist party, marked an escalation in the country’s political violence and sparked allegations of government negligence - even outright complicity. It also bolstered fears that Tunisia’s transition to democracy will be far more chaotic than originally hoped.

“This is a sad day that shook the country regardless of our differences,” Jebali said in an address to the nation, where the capital city still smelled of the tear gas lobbed at protesters angry over the killing.

“We are at a crossroads, and we will learn from it to make a peaceful Tunisia, secure and pluralist, where we may differ but not kill each other.”

The ruling coalition, led by Jebali’s moderate Islamist Ennahda party, had been in stalled negotiations with opposition parties to expand the coalition and redistribute ministerial portfolios in an effort to calm the country’s factious politics. Elections had been expected for the summer, but an exact date depended on lawmakers finishing work on a new constitution.

Jebali said the new ministers in the technocratic government “would not belong to any party and its task would be limited to organizing elections as soon as possible with a neutral administration.” The statement implied Jebali would be leading the government and that its selection was imminent.

Tunisians overthrew their long-ruling dictator Zine El Abidine Ben Ali in January 2011, kicking off a wave of pro-democracy uprisings across the Middle East and North Africa that have met with varying degrees of success.

With its relatively small, well-educated population of 10 million, Tunisia has been widely expected to have the best chance of successfully making the transition to democracy. Its first post-dictatorship election ended with the moderate Islamists of Ennahda in a coalition with two secular parties.

With the fall of the country’s secular dictatorship, however, hard-line Islamist groups also have flourished, and there were a string of attacks by ultraconservative Muslims known as Salafis against arts, culture and people they deemed to be impious.

In the past few months, there also have appeared the Leagues to Protect the Revolution, groups that say they are fighting corruption and seeking out remnants of the Ben Ali regime.

In practice, opposition leaders such as Belaid said, the leagues became Ennahda-backed goon squads that attacked opposition rallies.

Last weekend there was a string of attacks against such meetings, including a rally held by Belaid’s Popular Front in northern Tunisia.

Belaid, a lawyer, was shot point-blank as he left his house in Tunis on Wednesday morning.

He was taken to a nearby clinic where he died. His wife told French Radio RTL hewas shot twice in the head, once in the neck and once in the heart.

“He died for the country. He died for democracy,” Basma Belaid said. “He was threatened all the time,” she added, holding Ennahda directly responsible for his death.

Information for this article was contributed by Raf Casert, Sarah DiLorenzo and Bradley Klapper of The Associated Press.

Front Section, Pages 5 on 02/07/2013