Mutassim Gaddafi, the fifth son of ousted leader Muammar Gaddafi, was captured by rebel forces near the besieged town of Sirte, media reported late on Wednesday.
Col. Abdullah Naker of the NTC, quoted by Al Arabiya, said Mutassim was captured at his family home in Sirte. The news sparked celebratory gunfire in several cities, the BBC reported.
Mutassim, 34, was a national security advisor to his father and was widely seen as a rival to his brother Saif al-Islam in the race to succeed his father. He was in command of the defense of Sirte.
The uprising against the Gaddafi regime began in February.
NATO launched Operation Unified Protector in late March, following a UN resolution authorizing the use of military force to protect Libyan civilians from attacks by forces loyal to Gaddafi. The operation was extended for another 90 days in late September.
Following months of fierce fighting that has claimed hundreds of lives, the Libyan Transitional National Council has established control over most of the country's territory, including the capital of Tripoli.
Gaddafi loyalists, however, still maintain control of several Libyan towns, including Gaddafi's home town of Sirte, which has been a site of heavy fighting for the past few weeks.
