Belgian police arrested five people suspected of having ties with a terrorist group after swooping down on their homes in a Brussels suburb. The prosecutor’s office said the arrests were related to a case not associated with Thursday’s attack in Paris.

Two of the four raids were conducted in Brussels’ infamous Molenbeek district, where the mastermind of the November 2015 terrorist attack in Paris, Abdelhamid Abaaoud, as well as one of the main suspects, Salah Abdeslam, used to live amongst the area’s predominantly Muslim population.

Searches were also carried out in the municipality of Ganshoren in the Brussels Region, some five kilometers from the capital, and in the municipality of Roosdaal, about 30 kilometers west of Brussels.

“In all, five persons were arrested and taken in for questioning,” the prosecutor’s office said in a statement on Friday, adding that all of them “are suspected of participating in the activities of a terrorist group,” as cited by AFP.

Police discovered a cache of weapons during the raids, which included two handguns, a bullet-proof vest, and ammunition. Apart from the hidden arsenal, drugs, namely cannabis, were also found.

The suspects will now appear before a court that will determine if they will remain in custody.

While the arrests were made on the heels of the attack in Paris on Thursday, when a police officer was killed and two people were injured on the Champs Elysees, the prosecutor’s office stressed that the raids had been carried as part of a separate investigation, which is unrelated to the latest attack in France. The suspects are not believed to have links to either the terrorist attacks in Paris of November 2015 or those on Brussels’ metro and Zaventem airport in March of 2016.

A series of synchronized suicide attacks and armed assaults ripped through the French capital on November 13, 2015, claiming the lives of 130 people, including 89 at the Bataclan Theater. The state of emergency that was imposed afterwards has not been lifted since, as France continues to be a regular target for terrorists.

On Thursday, a gunman, identified as a 39-year old French citizen named Cheurfi, fired shots at policemen on the Champs Elysees, murdering Xavier Jugele, a 37-year-old police officer, while injuring two other officers and a German woman who was passing by as the incident unfolded. A note reportedly containing addresses, including that of France’s anti-terrorist agency DGSI, police departments, and gun shops, was found near Cheurfi’s body.

By coincidence, Jugele had been present during a symbolic reopening of the Bataclan Theater last year, which highlighted a performance by Sting.

While responsibility for both the November Paris attack and the one on Thursday have been claimed by Islamic State (IS, formerly ISIS/ISIL), French authorities have found no evidence linking the suspect to the terrorist group so far. IS’s claims that the attacker was a Belgian citizen have been dismissed by Brussels as false.

Last March, Brussels itself became the victim of a large terrorist attack, when twin suicide blasts rocked Zaventem Airport and another explosion targeted the city’s Maalbeek metro station, killing over 30 people and injuring dozens more. The assailants were also found to have been involved in plotting the Paris bloodshed of November 2015.