Tunisia's Interior Ministry on Friday banned a conference by the North African country's most prominent ultraconservative Islamic group, setting up the possibility of a confrontation over the weekend.

The ministry statement, which appeared on their Facebook site, said Ansar al-Shariah's annual conference to be held in Tunisia's holy city of Kairouan was not in compliance with the laws governing assembly and was a threat to public order.

Part of the ultraconservative salafi Muslim trend that gained popularity following the overthrow of Tunisia's secular dictatorship in 2011, Ansar al-Shariah calls for the strict application of Islamic law.

The group's leader, Seifallah Ben Hassine, is wanted in connection with an attack by a mob on the U.S. Embassy in Tunisia last September. Salafi groups have also been accused of attacking cinemas, art galleries and police stations.

The ministry statement said that the right to assembly was protected in the country, but only in the framework of the existing laws.

"Those who attack the state and its institutions, attempt to foment anarchy, threaten stability, or incite violence and hate must take full responsibility," the ministry statement said.

The decision, taken even as followers of Ansar al-Shariah have been arriving in Kairouan, sets up a confrontation between the government, which is led by the moderate Islamist Ennahda Party and Ansar al-Shariah.

The group's spokesman, Seifeddine Rais, warned the state in a news conference Thursday against police intervention against the conference.

"If the government tries to stop the Kairouan congress, it will bear full responsibility for any blood spilled," he said in a mosque where the conference was held. "The greater the pressure put on us, the greater the risk of an explosion."

He added that the group had not applied for a permit to hold their conference, which last year featured martial arts contests and displays of horsemanship, because "when we preach the words of God we do not need authorization."