The president of Libya's Olympic Committee Nabil al-Alam was kidnapped by gunmen in the centre of Tripoli and taken to a secret location, AFP reports.
"Nine gunmen posing as members of the Libyan army removed Mr. Alam from his car in the centre of the city at around 3:00 pm (1300 GMT) and took him to an unknown location," Alam's office chief Arafat Juwan said.
The army and interior ministry were not aware of any arrests, he added.
Alam's abduction comes a few days before the planned departure of Libya's five representatives to the London Olympic and Paralympic Games, which are set to begin on July 27.
Libyan athletes will be participating in judo, the marathon, the women's 100-metre dash and weightlifting.
Jacques Rogge, President of the International Olympic Committee (IOC), said that he had been in contact with the NOC in Libya.
"We are in contact to know about what happened," said the 70-year-old Belgian, who was giving a pre-London Games telephone conference from IOC headquarters in Lausanne, Switzerland.
"We expressed our grave concern and offered any possible help we can give. I have really no more details on what happened than the media do. Hopefully this will evolve favorably."
Before last year's revolt which toppled the regime of Moamer Kadhafi, the Libyan Olympic Committee was headed by the strongman's eldest son Mohammed, who has since sought refuge in Algeria with other family members.