TUNIS -- Tunisia's Islamist government on Tuesday declared the largest radical Islamist movement in the country a terrorist organization, broadening its crackdown on Islamist extremists and distancing itself from their violent activities.
Prime Minister Ali Laarayedh announced the decision, saying the group, Ansar al-Shariah, was behind two political assassinations this year and other attacks on police officers and soldiers. The group and its leader, Abu Iyadh, have also been accused of orchestrating an attack on the American Embassy in Tunis, the nation's capital, last September.
The move is a further step by the governing party, Ennahda, to outlaw radical Islamists, despite internal sympathies for the various groups. The government has come under pressure to resign since the assassination of one of the politicians, Mohamed Brahmi, in July, and Ennahda is fighting for its political survival.
Opponents have accused Ennahda of being soft on radical groups, including Ansar al-Shariah. Up to a year ago, the government was trying to encourage such groups to join the political process, contending that only a few among them advocated terrorism.
All religious groups were banned under the previous dictatorships. But since the popular uprising that ousted President Zine el-Abidine Ben Ali in 2011, religious organizations have enjoyed newfound freedoms to preach and form associations.
There are sympathizers within Ennahda for jihadist and other radical Islamist groups, and they deny that such organizations are involved in violence inside Tunisia. Many of the individuals from the various camps were imprisoned together under Mr. Ben Ali's authoritarian rule.
Thousands of political and religious prisoners were released after the revolution under a general amnesty, among them Abu Iyadh, a Tunisian jihadist who fought alongside Osama bin Laden at Tora Bora in Afghanistan. He escaped Afghanistan in 2001 and after two years on the run was detained in Turkey in 2003 and deported to Tunisia, where he was jailed.
He gave frequent interviews to journalists after his release in 2011 and claimed his group, Ansar al-Shariah, was focusing on peaceful preaching.
Yet a string of attacks in the past year have forced the government to investigate his movement.
The attack on the American Embassy, in which 100 vehicles were burned and the American school adjacent to the embassy compound was looted, put the government on alert, coming two days after the assault on the American mission in Libya that killed the ambassador and three other Americans.
American intercepts later revealed that Abu Iyadh was in touch with Al Qaeda in organizing the attack, according to government officials here. The attack was followed by the assassination of two secular politicians, Chokri Belaid in February and Mr. Brahmi in July.
The government began to move against Ansar al-Shariah, banning its annual congress in May and battling its supporters in the streets of a Tunis suburb. In the months since, hundreds of members of the movement have been detained.
At the same time, militants began insurgent activities on Tunisia's western border with Algeria, laying mines and ambushing soldiers. Ten soldiers have been killed since April, eight of them in an ambush in July that shocked the nation.
The government now says that the movement as a whole is involved in a campaign of violence.
"Ansar al-Shariah is involved in assassinations, and responsible for collecting of weapons, for planning other assassinations and attempting to attack security offices," the prime minister said at a news briefing. He said the government had evidence and confessions from suspects.
"The structure of this organization is based on a military structure, and we took the decision to classify it as a terrorist organization."
Branding Ansar al-Shariah a terrorist group could force it and its thousands of young followers underground, warned Fabio Merone, a researcher from Dublin City University who has studied it.
"It is a big group and rooted in society," he said. The movement does not openly espouse a terrorist agenda, and while some elements within it may be involved in terrorism, many are not, he said. "We were expecting the government to distinguish between the two," he added.
This article originally appeared in The New York Times.