Salah Abdeslam, the only surviving suspect in last year's Paris massacre, has told investigators he was planning to "restart something" in Brussels, Belgium, when he was arrested last week, Belgian Foreign Minister Didier Reynders said Sunday.
Abdeslam, 26, was thought to be the eighth suspect who ISIS said took part in the coordinated attacks Nov. 13 in Paris, which killed 130 people. Seven other attackers were killed or blew themselves up.
Abdeslam had intended to kill himself, as well, in a suicide bombing at the Stade de France in Paris, where the French and German national soccer teams were playing that day, "but he stopped," Reynders said.
"We don't know why, but he stopped," Reynders added at the Brussels Forum of the German Marshall Fund of the United States, a gathering of North American and European political, business and intellectual leaders.
Paris prosecutor Francois Molins also said Saturday that Abdeslam was to have targeted the Stade de France but backed out — comments which lead his Belgian lawyer on Sunday to threaten legal action for violating the confidentiality of the investigation.
"Salah is of great importance to this investigation. I would even say that he is worth gold. He is cooperating, he is communicating, he is not insisting on his right to silence. I think it would be worthwhile now to give things a bit of time ... for investigators to be able to talk to him," attorney Sven Mary said.
Reynders said authorities were taking Abdeslam's claim of a new attack seriously because "a lot of weapons, heavy weapons," were found leading up to Friday's arrest. Moreover, Abdeslam had gathered a large network of people around him in Brussels, Reynders said.
Interpol issued a statement Saturday warning European nations that Abdeslam's accomplices could try to flee.
Belgian authorities charged Abdeslam and an alleged accomplice who was with him with terrorist murder Saturday. Justice Minister Koen Geens said Sunday on RTL television that Abdeslam's initial court appearance was scheduled for Wednesday and that extradition to France could take more than two months.
Counterterrorism officials told NBC News that Abdeslam was believed to have wide knowledge of ISIS' inner workings and could have information that could help them thwart other terrorist attacks.
Abdeslam was shot in the leg when he and the suspected accomplice were captured Friday during a massive anti-terrorism raid in Brussels.
He was discharged from the hospital Saturday. Mary, his lawyer, told the Belgian newspaper La Capitale that his client was "frightened and weak."
This story first appeared on NBCNews.com.