Nigerian authorities announced Saturday that they had arrested two suspected leaders of the jihadist group Ansaru, responsible for the 2022 attack on a prison near the capital Abuja, which allowed hundreds of inmates to temporarily escape.

Mahmud Muhammad Usman and Mahmud al-Nigeri were captured during a "targeted operation" carried out "between May and July," Nigeria's national security adviser, Nuhu Ribadu, told reporters on Saturday.

According to Ribadu, the two men are leaders of the Ansaru group, which split from Boko Haram in 2012. Ansaru later aligned itself with Al-Qaeda in the Islamic Maghreb (AQIM). The United States designated Ansaru and Boko Haram as "foreign terrorist organizations" in 2013.

After the split, the group settled in Kano, Nigeria's second largest city (nearly five million inhabitants) located in the north of the country, in the eponymous state.

"These two men have been on Nigeria's most wanted list for years. Together, they have carried out multiple attacks against civilians, security forces, and critical infrastructure," Ribadu said.

The two men were also on international wanted lists, he said.

Mahmud Usman is also known as Abu Bara and Mahmud al-Nigeri as Mallam Mamuda. They have also been involved in several high-profile kidnappings in the central and northwest parts of the country.

- Kidnappings -

President Bola Tinunbu, through his spokesperson on social media, hailed a "significant step forward in the war against terrorism" for this country, which has been plagued by jihadists in the northeast for nearly two decades.

"The capture of Abu Bara and Mallam Mamuda, the group's leader and deputy commander respectively, marks one of the most significant successes to date in our continued efforts to rid Nigeria of the terrorist threat," Ribadu said.

Ansaru members, many of whom were educated in the West, had said they rejected Boko Haram leader Abubakar Shekau because he was too extremist.

But the group has since descended into the same violence it initially denounced in Boko Haram.

According to Mr. Ribadu, Mahmud Usman and Mahmud al-Nigeri organized several large-scale kidnappings and armed robberies, using these methods to "finance terrorism over the years."

In an attack in July 2022, jihadists used firearms and explosives to enter Kuje prison, a medium-security facility located about 40 km from the capital, Abuja.

Several hundred prisoners were then released, before being recaptured by the police.

Ansaru later claimed responsibility for the attack.

The group has also been accused of blowing up railway tracks and attacking a train from the capital Abuja to the northwestern city of Kaduna, also in 2022. Eight people were killed and dozens more were kidnapped and held hostage for several months.

In 2012, the group had already attacked a police station in the capital, killing officers and freeing detainees.

The United States claims that Ansaru also kidnapped and executed seven foreign construction workers in 2013.

More recently, Nigeria has also had to deal with criminal gangs that are increasing kidnappings and ransom demands in the center and northwest.