Fighters with Libya's National Transitional Council say forces loyal to former Libyan leader Moammar Gadhafi have killed at least 15 guards in an attack outside a key oil refinery in the coastal city of Ras Lanuf.

Provisional authority forces say armed Gadhafi fighters approached the refinery in a column of vehicles early Monday, attacking the guards posted outside the facility, which is controlled by NTC forces. At least two guards were wounded in the battle at the major oil port.

On Sunday, provisional authority fighters returning from the oasis city of Bani Walid met fierce resistance by Gadhafi loyalists using mortars, Grad rockets and rooftop snipers.

The clashes show that Mr. Gadhafi's forces are still able to mount successful attacks against NTC fighters, who are now in control of most of the country.

Meanwhile, Niger's government says an army patrol intercepted a convoy carrying Mr. Gadhafi's son, Saadi, and nine other people after they crossed the desert from Libya.

Niger's justice minister said Sunday the vehicles were traveling toward the northern city of Agadez, where other Libyan loyalists are believed to have fled, including three generals and Mr. Gadhafi's security chief.

The justice minister said he expected the group to be transferred to the capital, Niamey, sometime this week and that Niger would fulfill its international obligations. But he said the government has no plans to arrest Saadi Gadhafi for now, as the International Criminal Court in the Hague has not issued a warrant for him.

Saadi, the highest profile member of the former Libyan government to enter Niger, had attempted to negotiate an end to the fighting in Libya with the ruling National Transitional Council late last month after its fighters swept through the capital, Tripoli.

Interim Libyan Prime Minister Mahmoud Jibril said the NTC would form a more inclusive interim government within 10 days.

Late Sunday, Algerian officials said they would officially recognize the NTC as Libya's rightful authority, but only once a “representative government was in place.”

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