Niger's justice minister says a son of ousted Libyan leader Moammar Gadhafi has arrived in Niger, as Libya's provisional government forces pushed their way into the oasis town of Bani Walid, one of Mr. Gadhafi's last remaining strongholds.

Niger's Marou Adamou told journalists Sunday that Mr. Gadhafi's son Saadi was intercepted after entering into Libya's southern neighbor in a convoy of about ten people.

Meanwhile, anti-Gadhafi fighters said Sunday they control big chunks of Bani Walid, especially to the north. They say pro-Gadhafi forces are still fighting to keep control of the town's center.

Anti-Gadhafi reinforcements poured into the area just outside the town Sunday. NATO warplanes flew overhead after also providing air support the day before. Smoke billowed from the town after intense fighting Saturday.

NATO said its warplanes hit a multiple rocket launcher, a tank and two armed vehicles near Bani Walid on Saturday. NATO also hit targets near the pro-Gadhafi strongholds of Sirte and Sabha.

The National Transitional Council said anti-Gadhafi forces moved on Bani Walid Friday after Gadhafi loyalists fired a barrage of rockets at NTC positions.

NTC forces have expressed confidence they are close to victory despite the continued fighting.

NTC fighters reportedly are gathering outside other strongholds of pro-Gadhafi forces, including Mr. Gadhafi's home city of Sirte.

Mr. Gadhafi's whereabouts are unknown. Late Saturday, Guinea Bissau's prime minister said his country would welcome the ousted Libyan leader should he seek exile in that west African country. Guinea Bissau had strong ties to Mr. Gadhafi's government when he was in power.

Mr. Gadhafi's son Saadi was the center of conflicting reports recently. A commander of anti-Gadhafi forces said last month the son had contacted him and offered to surrender. But U.S. news network CNN reported that Saadi denied making the offer, saying he would “rather surrender to a real government than to those people.”