Tunisia says its military forces have killed at least nine militants during an operation in the west-central part of the country.

Interior Ministry spokesman Mohamed Ali Aroui said that the operation was carried out in the late hours of Saturday in Gafsa region.

“Nine terrorists were killed last night (Saturday) in the mountains of Sidi Aich,” said the Tunisian official, adding that security forces also confiscated arms and explosives from them.

Reports say the militants were members of the so-called Okba Ibn Nafaa Brigade, which is believed to be behind the deadly attack on the Bardo Museum in the capital, Tunis on March 18.

Most of the 22 victims of the attack were reportedly tourists from Italy, Japan, France, Spain, Colombia, Australia, Britain, Belgium, Poland and Russia.

Meanwhile, thousands of Tunisians are expected to take part in a solidarity march in the capital on Sunday to denounce terrorism.

French President Francois Hollande and Italy’s Prime Minister Matteo Renzi are also among the foreign dignitaries that are expected to take part in the demonstration.

Tunisian Tourism Minister Salma Elloumi Rekik said on Saturday that the attack was “a big blow, but this blow did not kill us, it made us stronger.”

The people of Tunisia, the birthplace of pro-democracy protests across North Africa and the Middle East, revolted against the Western-backed dictator, Zine El Abidine Ben Ali, in 2011. Despite the political stability since then, insurgency and terrorists still threaten the North African country.