Screen grab
Amedy Coulibaly
Earlier, Belgian authorities had detained a man for arms dealing and are investigating whether he supplied one of the Islamist gunmen who together killed 17 people in Paris last week, prosecutors said on Thursday.
He confessed that he had been in touch with Amedy Coulibaly, the militant who took hostages in a Jewish supermarket in the French capital and was later killed by security forces.
Police searched his home and allegedly found documents relating to negotiations over the sale of arms.
According to police officials, the Scorpion machine gun and the Tokarev handgun used by Coulibaly during his attack on the kosher supermarket, which resulted in the deaths of four Jewish Parisians, came from Brussels and Charleroi.
The man said he also swindled in a car sale, but police later found evidence that the two had been negotiating the sale of ammunition for a 7.62 mm caliber firearm.
A Belgian arms dealer confesses to supplying Paris attackers with weapons.
"The man is being held by the judge in Charleroi on suspicion of arms dealing," a spokesman for Belgium's federal prosecution said. "Further investigations will have to show whether there is a link with the events in Paris," he added.
The Kalashnikovs and rocket launchers used by the Kouachi brothers in the Charlie Hebdo attack, which killed 12, were purchased by Coulibaly near the Gare du Midi in Brussels for less than $5,867 (€5,000/£3,870), The Telegraph reports.
Earlier this week, Al Qaeda in Yemen claimed responsibility for the attack on the French satirical newspaper Charlie Hebdo, saying the assault on the paper's offices was ordered by the Islamist militant group's leadership, according to a video posted on YouTube. Those claims have met scrutiny.
The search continues for France's most-wanted woman, Hayat Boumeddienne, Coulibaly's common-law wife, who is believed to have crossed the border to Spain to fly from Istanbul, where she later crossed into Syria.
Police suspect she might have had a hand in Coulibaly's supermarket hostage-taking, though she was not identified among the dead or wounded, AFP reports.
The couple lived in a modest apartment in a poor suburb south of Paris.
Boumeddienne reportedly accompanied Coulibaly several times to a forest in southern France to shoot a crossbow. Le Monde published several photos of the couple holding up the weapon, with Boumeddienne wearing her niqab.
A court in Antwerp is due to deliver its verdict on 46 people accused of recruiting young men to join jihadists or of becoming jihadists in Syria, Belgium's largest Islamist militant trial to date. The court was to have given its verdict this week, but it was delayed for a month after the Paris violence.