Libya's new leaders said Sunday they will try Moammar Gadhafi's son, Seif al-Islam, in Libya and will not hand him over to the International Criminal Court in The Hague, Netherlands, where he is charged with crimes against humanity.

The leaders also announced the capture of Gadhafi's former intelligence chief, Abdullah al-Senoussi, who is also wanted by the ICC on the same charge.

They said Senoussi was detained Sunday in the southern desert, not far from where Seif al-Islam was seized by militiamen from the western town of Zintan a day earlier. Gadhafi was later transported to Zintan.

Libya's transitional Prime Minister Abdurrahim el-Keib visited the town on Saturday and praised the capture of Seif al-Islam as marking a new chapter for the country. Libyan transitional authorities said the two captured men would be given a fair trial in Libya.

The ICC issued arrest warrants for Seif al-Islam, his father, and Senoussi in June, for violently suppressing a pro-democracy uprising. ICC prosecutor Luis Moreno Ocampo plans to travel to Libya in a week to discuss arrangements for the trial.

In a statement Saturday, the U.S. State Department said the capture and trial of Seif al-Islam “would be another step away from a four-decades-long dark chapter in Libyan history” and help the Libyan people achieve “the peaceful and democratic future they deserve.”

Washington also urged Libya to treat all prisoners humanely and in accordance with international standards. Transitional fighters who seized Moammar Gadhafi in his hometown of Sirte on October 20, were seen beating him before he died, prompting international concern about his son's treatment in custody.

Transitional forces launched the uprising in February and drove the senior Gadhafi out of Tripoli in August, ending his 42-year rule.