TUNIS -- New political uncertainties gripped Tunisia on Thursday, a day after officials moved quickly to contain the fallout from the assassination of a leading opposition figure. A plan to reshape the Islamist-led administration in favor of a national unity government encountered strong resistance as protesters again demonstrated on the streets of the capital and elsewhere.
The country's dominant Ennahda Party rejected the plan to dissolve the government, as proposed Wednesday by Prime Minister Hamadi Jebali.
"The prime minister did not ask the opinion of his party," Abdelhamid Jelassi, Ennahda's vice president, said in a statement reported on the party's Web site and in Tunisian news reports. "We in Ennahda believe Tunisia needs a political government now. We will continue discussions with others parties about forming a coalition government."
The statement appeared to inject a new element of political tension into an already fraught and fragile situation in Tunisia, the birthplace of the Arab Spring uprisings more than two years ago.
Anxiety about the assassination of the opposition figure, Chokri Belaid, also reverberated to Egypt, where security officials said plainclothes guards had been assigned to guard the homes of prominent opponents of Egypt's Islamist-dominated government. The worries were amplified because of a fatwa issued by a hard-line Egyptian cleric saying that opponents of President Mohamed Morsi should be killed. The fatwa specifically targeted Mohamed ElBaradei, a former United Nations diplomat and leader of Egypt's largest secular-leaning opposition bloc, which led him to request the protection. "Regime silent as another fatwa gives license to kill opposition in the name of Islam," Mr. ElBaradei wrote in a Twitter message. "Religion yet again used and abused."
Residents of Tunis said hundreds of protesters -- far fewer than on Wednesday -- took to the streets on Thursday while the French Embassy said on its Web site that it would close its schools in the capital on Friday and Saturday for fear of renewed outbursts of violence.
France is the former colonial power in Tunisia and has traditionally had a strong diplomatic presence here.
In the southern mining city of Gafsa, riots broke out and the police fired tear gas at demonstrators who threw stones, a local radio station reported. The city is known as a powerful base of support for Mr. Belaid, the slain politician.
Some reports also spoke of tear gas being fired in the capital as protesters again converged on the Interior Ministry headquarters in what has been depicted as the worst crisis since the revolt that overthrew Tunisia's autocratic leader, Zine el-Abidine Ben Ali, in January 2011.
Fresh unrest loomed with the prospect of a general strike on Friday on the same day as the funeral of Mr. Belaid, likely to be a highly emotional event in its own right.
Additionally, Friday, the Muslim holy day, has been associated with unrest and protest since the beginning of the revolts that overthrew or challenged dictatorial regimes across the Arab world and North Africa. Mr. Belaid was one of Tunisia's best-known human rights defenders and a fierce critic of the ruling Islamist party.
His killing placed dangerous new strains on a society struggling to reconcile its identity as a long-vaunted bastion of Arab secularism with its new role as a proving ground for one of the region's ascendant Islamist parties.
The explosion of popular anger, which led to the death of a police officer in the capital, posed a severe challenge to Ennahda, which came to power promising a model government that blended Islamist principles with tolerant pluralism.
Mr. Belaid was shot and killed outside his home in an upscale Tunis neighborhood as he was getting into his car on Wednesday morning. The interior minister, citing witnesses, said two unidentified gunmen had fired on Mr. Belaid, striking him with four bullets.
The killing, which analysts said was the first confirmed political assassination here since Mr. Ben Ali was driven from power, was a dark turn for the country that has come to symbolize the Arab Spring movement. It resonated in countries like Egypt and Libya that are struggling to contain political violence while looking to Tunisia's turbulent but hopeful transition as a reassuring example.
The authorities have not announced any arrests in connection with Mr. Belaid's killing, saying only that witnesses said the gunmen had appeared to be no more than 30 years old. Among Mr. Belaid's colleagues and relatives, suspicions immediately fell on the hard-line Islamists known as Salafists, some of whom have marred the transition with acts of violence, including attacks on liquor stores and Sufi mausoleums.
Mr. Belaid, a leading member of Tunisia's leftist opposition alliance, criticized the governing party for turning a blind eye to criminal acts by the Salafists, and had received a string of death threats for his political stands, his family said.
In a chilling prelude to his death, in a television interview on Tuesday, Mr. Belaid accused Ennahda of giving "an official green light" to political violence. Separately, he accused "Ennahda mercenaries and Salafists" of attacking a meeting of his supporters on Saturday.
His wife, Besma Khalfaoui, blamed Ennahda and told Tunisia's state news agency that the authorities had ignored her husband's pleas for protection during four months of death threats.
The party vigorously denied any role in the killing, but the damage to its reputation seemed difficult to repair.
Salman Shaikh, director of the Brookings Doha Center, said the assassination was a blow to the aspirations of Islamist parties taking the reins in democratic transitions in the region, most notably in Egypt and Tunisia. In Egypt, he said, the Islamists have failed to build consensus and trust, relying instead on a narrow majoritarianism. In Tunisia, he said, they built a coalition with liberals but failed to take a stand against more hard-line Islamists competing for support on their right.
"Facing down extremists -- Islamists find that very difficult," Mr. Shaikh said.
In Tunisia, he said, the extremists included not only Salafis but more militant actors closer to Al Qaeda. "They have not been very quiet in terms of their intentions, and yet Ennahda has not taken them on," he said.
In Tunisia, some hoped that the killing would serve as a warning not just about the dangers of political violence, but also about the authorities' refusal to confront it. Amna Guellali, a Human Rights Watch researcher based in Tunis, said the group had documented numerous attacks on activists, journalists and political figures by various groups, including the Salafis.
"The victims filed complaints to local tribunals, but never heard anything back," she said. "There is a trend of impunity. This impunity can lead to emboldening" attackers.
"Yesterday, Chokri called for a national dialogue to confront political violence," she said. "This just adds to the tragedy."
Monica Marks and Kareem Fahim reported from Tunis, and Alan Cowell from Paris. Reporting was contributed by Mayy el Sheikh from Cairo; David D. Kirkpatrick from Antakya, Turkey; and Rick Gladstone from New York.
This article originally appeared in The New York Times.