BENGHAZI, Libya - Libyan rebels said Sunday that over 10,000 prisoners arrested by embattled leader Muammar Gadhafi's government had been freed since the rebel forces took control of the capital Tripoli.

But, according to rebel military spokesman Col. Ahmed Bani, about 50,000 prisoners were still missing, and it would be "catastrophic" if they had already been killed after being arrested.

Bani meanwhile said at a press conference Sunday that Libya's gas pipeline to Europe had been repaired.

Head of the Libyan National Transitional Council (NTC) Mostafa Abdel Jalil Saturday vowed fair trials for those having worked with Gadhafi, and said the reward for killing or capturing the fallen leader could be increased.  

On the battle front, the rebel forces were closing in on Gadhafi's hometown of Sirte, one of the last few areas still held by troops loyal to the toppled Libyan leader, from the west and east. Rebel leaders have vowed to take Sirte by force if their negotiations with the region's tribal leaders fail.