"These first statements, which should be taken cautiously, leave a whole series of issues that Salah Abdeslam must explain," he added.
Abdeslam has been formally charged in connection with the November massacre, but will oppose his transfer to France, his lawyer said earlier.
However, defence lawyer Sven Mary told reporters at federal police headquarters in Brussels that Abdeslam "will refuse his extradition at this stage".
"He is cooperating with Belgian justice," he said.
