TRIPOLI, Libya — Libyan fighters have surrounded the ousted dictator Moammar Gadhafi, and it is only a matter of time until he is captured or killed, a spokesman for Tripoli’s new military council said Wednesday.

Anis Sharif would not say where Gadhafi had been found, but said he was still in Libya and had been tracked using high technology and human intelligence. Gadhafi is trapped within a 40-mile- (60 kilometer-) radius area surrounded by rebels, he said.

“He can’t get out,” said Sharif, who added the former rebels are preparing to either detain him or kill him.

Locating Gadhafi would help seal the new rulers’ hold on the country. The announcement came after convoys of Gadhafi loyalists, including his security chief, fled across the Sahara into Niger in a move that Libya’s former rebels hoped could help lead to the surrender of his last strongholds.

Some former rebels depicted the flight to Niger as a major exodus of Gadhafi’s most hardcore backers. But confirmed information on the number and identity of those leaving was scarce given the vast swath of desert — over 1,000 miles (1,600 kilometers) — between populated areas on the two sides of the border.

In Niger’s capital, Niamey, Massoudou Hassoumi, a spokesman for the president said Gadhafi’s security chief had crossed the desert into Niger on Monday accompanied by a major Tuareg rebel.

The government of Niger dispatched a military convoy to escort Mansour Dao, the former commander of Libya’s Revolutionary Guards who is a cousin of Gadhafi as well as a member of his inner circle, to Niamey.

Dao is the only senior Libyan figure to have crossed into Niger, said Hassoumi, who denied reports that Gadhafi or any member of his immediate family were in the convoy.