Libyan officials say they have captured Seif al-Islam Gadhafi alive and in good health and are holding him in the western city of Zintan.
The country's interim Prime Minister Abdurrahim el-Keib told a news conference late Saturday that Seif al-Islam will receive a fair trial and be guaranteed rights under Libyan and international law.
He also said he hoped the arrest of Seif al-Islam will be the last action of the revolution and the first step to building a new Libya.
The news conference was frequently interrupted by cheering spectators who clapped and shouted “God is great.”
Earlier, a military spokesman said Libyan forces had caught Seif al-Islam and several of his aides near the southern town of Obari. The town is close to Libya's border with Niger, which has already given asylum to his brother, Saadi.
Libyan officials said it appeared that Seif al-Islam's aides were trying to smuggle him into Niger. The country's president, Mahamadou Issoufou, said last week no decision had been made about what to do if he requested asylum.
Following word of his arrest, Libyan officials released a picture allegedly of Seif al-Islam showing him reclining on a bed with bandages wrapped around the fingers of his right hand. It is unclear how he sustained those injuries.
Video from Tripoli on Saturday showed Libyans celebrating news of Seif al-Islam's arrest. He is wanted by the International Criminal Court on charges of crimes against humanity for helping to lead the crackdown on protests during his father's rule.
Last month, ICC prosecutor Luis Moreno-Ocampo said the court had been in talks with Seif al-Islam about a possible surrender and making sure he gets a fair trial.
Moreno-Ocampo says he plans to travel to Libya soon to discuss with Libyan authorities where Seif al-Islam will be tried.
Officials with the European Union urged Libyan authorities to make sure Seif al-Islam is brought to justice in cooperation with the ICC.
International rights groups are closely watching the process surrounding Seif al-Islam's detention, especially following the murky circumstances surrounding the capture and death of his father Moammar Gadhafi in custody last month.
The ICC issued its arrest warrants against Seif al-Islam last June, along with warrants for his father and former Intelligence Chief Abdallah Senoussi. So far, Senoussi still is unaccounted for by the authorities.
