TARHOUNA, Libya — Convoys of Moammar Gadhafi loyalists, including his security chief, fled across the Sahara Desert into neighboring Niger on Tuesday in a move that Libya’s former rebels hoped could undermine the ousted leader’s support in his last strongholds in the country and help lead to their surrender.

Still, efforts to negotiate the peaceful handover of one of the most crucial of those strongholds, the city of Bani Walid, proved difficult.

Tribal elders from Bani Walid who met Tuesday with former rebels were met by angry residents of the city, including Gadhafi supporters, who fired in the air to intimidate them, sending them fleeing, mediators said.

The round of talks illustrated how many in Bani Walid remain deeply mistrustful of the forces that have seized power in the country and reluctant to accept their rule, even beyond a simple loyalty to the ousted leader.

The scope of the flight to Niger was not immediately clear. Some former rebels depicted it as a major exodus of Gadhafi’s most hardcore backers. But information on the number and identity of those fleeing was scarce as they made their way across the vast swath of desert — over 1,000 miles — between any populated areas on the two sides of the Libya-Niger border.

Gadhafi himself is not in the convoys, the U.S. State Department said.