Tunisian security forces decimated the leadership of a Tunisian extremist group linked to al-Qaeda’s North African branch, including the man identified as the “operational chief” of the attack this month on the National Bardo Museum that killed 22 people, mostly foreign tourists, the interior minister said Sunday.

Najem Gharsalli said Khaled Ben Hamadi Chaieb, also known as Lokman Abu Sakhr, an Algerian, handled the operational end of the March­ 18 massacre. Two gunmen were killed in the attack. Dozens of arrests have been made, five security officials fired and an officer charged with surveying the museum jailed.

Two other Algerians were among nine people killed Saturday by security forces in Gafsa, near the Algerian border, the minister told reporters, saying the leadership of the Okba Ibn Nafaa Brigade, which has killed dozens of security forces, was decimated.

Gharsalli proclaimed the “beginning of the war against terrorism” and revealed that Tunisia has acquired new equipment, “including drones.”

The announcement came as tens of thousands of Tunisians marched to the Bardo museum, where they were joined by a handful of foreign leaders for a ceremony. Among those present were French President François Hollande and Italian Prime Minister Matteo Renzi.

The international visitors were showing solidarity with Tunisia, whose fragile new democracy was deeply shaken by the museum attack.

The Islamic State group claimed responsibility for the massacre, and it was unclear what ties the Tunisian brigade might have with the group that has taken control of large swaths of territory in Iraq and Syria, with groups claiming affiliation in Libya and elsewhere. The presence of Algerians in the Okba Ibn Nafaa Brigade underscores the links with al-Qaeda in the Islamic Maghreb, the Algerian-based affiliate that in 2012 took over northern Mali and is known as AQIM.

Hollande said France will strengthen intelligence cooperation with Tunisia, and U.S. Ambassador Jake Walles, who also attended the ceremony, said Washington is working with Tunisian military and security forces “so that they have the tools, the equipment and the training that they need so they can do the job.”

Chaieb, the operational leader of the brigade, has been condemned to death several times in Algeria, and 21 arrest warrants had been issued for him, the minister said, adding that the Algerian was implicated in a July 2014 attack in which 15 Tunisian soldiers were killed near Mount Chaambi, near the Algerian border, and in a 2013 attack in which numerous soldiers’ throats were slit.