Jamal abu-Shaalah, a field commander of NTC, told Al Jazeera that the toppled leader had been seized, but it was not clear whether he was dead or alive.
Gaddafi is captured and is wounded, Abdel Majid, another NTC official, told the Reuters news agency.
"He's captured. He's wounded in both legs ... He's been taken away by ambulance," the senior NTC military official said.
Majid also said that Abu Bakr Younus Jabr, the head of Gaddafi's armed forces, was killed during the capture of Gaddafi.
The news came shortly after NTC claimed capturing Sirte, Gaddafi's hometown, after weeks of fighting.
NATO and the US state department said it cannot confirm the reports of Gaddafi's capture. He has not been seen since NTC fighters seized Tripoli, the Libyan capital.
Meanwhile in Benghazi, crowds gathered in the streets to start celebrating the reports of Gaddafi's capture.