PARIS (Reuters) - Lawyers defending the man believed to be the sole living suspect in Islamist militant attacks that killed 130 people in France last November have resigned from the case after months in which their client has refused to talk.

Salah Abdeslam, who has been held in solitary confinement near Paris since he was captured earlier this year, does not want to talk and no longer wants legal representation, his lawyers Frank Berton and Sven Mary said on BFM Television.

"We are convinced, and he told us so, that he will not talk and will use his right to remain silent. What can we do? I have said it from the beginning: if my client remains silent, I drop his defense," Berton said.

Berton, a high-profile French criminal lawyer, said that Abdeslam was refusing to talk because of the 24-hours-a-day camera monitoring in his high-security jail, conditions which the lawyers have repeatedly tried and failed to get changed.

"We have seen him slide away. Being watched all the time, with infrared at night, that drives one crazy, and that is a consequence of a political decision," he said.

Abdeslam's Belgian lawyer, Sven Mary, said the solitary confinement was causing Abdeslam to clam up.

"The real victims of this are the victims of the Paris attacks. They have a right to know," he said.

A lawyer for some of the victims of the Paris attacks said it was clear the suspect had gone back on a pledge to talk to investigators and that the round-the-clock monitoring of his cell had nothing to do with his silence.

"Salah Abdeslam is refusing to cooperate," said lawyer Samia Maktouf. "The video surveillance is just a pretext," she told reporters.

Abdeslam was spirited out of France and back to Belgium, his country of residence, by car in the hours after the attacks on Nov. 13. He was later captured in Belgium and handed over to France earlier this year.

French authorities suspect him of helping to organize the machine gun and suicide bomb assaults on a music venue, bars and a sports stadium and want to know if he was at one point supposed to play a direct role in the attacks, which were claimed by the militant group Islamic State. No date has yet been set for his trial.

(Reporting by Andrew Callus, Geert De Clercq and Brian Love; Editing by Mark Trevelyan)