mohammed Abdeslam brother of paris suspect pleads with his brother to surrender himself to the authorities

"I would tell him to surrender. That's the best solution," said Mohamed Abdeslam "But of course, if he has something to do with it, he must accept responsibility."

there is a "strong presumption" that another suspect linked to the attacks is at large, in addition to Abdeslam.

Another Abdeslam brother, Ibrahim, 31, was among the six terrorists who either killed themselves or were killed by police in a series of coordinated attacks across the French capital on Friday night that killed at least 129 people and wounded hundreds more. 

"These are not regular people," Mohamed Abdeslam, 29, said of his brothers. "You cannot have the slightest doubt that they have been prepared, that they must not leave any trace which would cause suspicion that they might do such things. And even if you saw them every day, their behavior was quite normal."

Police stopped Salah Abdeslam, 26, hours after the attacks, in a car on his way toward the Belgian border but let him go because he apparently hadn't yet been linked to the terrorist operation.

Both he and Ibrahim were previously known to authorities.Ibrahim tried to go to Syria and was sent back by the Turks in the beginning of 2015," Van Der Sypt said. "It was after that that we questioned him.

Both brothers were released, the federal prosecutor said, after they denied wanting to go to Syria.

He said Belgian authorities were also trying to keep an eye on Bilal Hadfi, one of the suicide bombers who struck outside the Stade de France, according to several sources. "We knew (Hadfi) was in Syria," Van Der Sypt said. "But what we didn't know is apparently he was back, as he blew himself up in Paris. But we had no knowledge of the fact that he was back in Europe."

None of the individuals identified so far in the Paris attacks has been on any U.S. watch lists.