The International Committee of the Red Cross (ICRC) has asked Libyan authorities to be allowed to visit Saif al-Islam Gaddafi in prison and expects the visit to take place soon, a senior ICRC official said on Monday.

He is an individual who must be protected ... We have made the request and think that we will have access very quickly to Mr Gaddafi, Yves Daccord, ICRC director-general, told a news briefing in Geneva.

Saif al-Islam, once thought likely to succeed his late father Muammar Gaddafi in power, was captured by Libyan fighters in Libya's remote southern desert on Saturday.

The independent humanitarian agency has visited some 8,500 detainees in nearly 60 places of detention throughout Libya since the conflict began in March, an ICRC spokesman said.

Worldwide, the ICRC insists on the right to interview prisoners of its choosing in private and make follow-up visits. It also hands over messages between inmates and their families.

Its confidential findings on conditions of custody and treatment of prisoners are given only to detaining authorities.

Concern about the conditions of Saif al-Islam's detention follows the treatment of his father, who was delivered dead to hospital after being filmed being beaten and abused by troops loyal to Libya's new authorities who captured him alive.

The new Libyan government says Saif al-Islam Gaddafi will be held in safety.

Libyan officials have also reported capturing Muammar Gaddafi's former spy chief Abdullah al-Senussi, who along with Saif al-Islam Gaddafi is the last surviving Libyan wanted for war crimes by the International Criminal Court in the Hague.

Libyan Prime Minister designate Abdurrahim El Keib said on Monday he needed to verify whether Senussi was indeed captured before being able to confirm it.

Libya says its own courts could judge the younger Gaddafi fairly, defying the U.N. war crimes court, which says it is right to try him at The Hague for crimes against humanity. The ICC has indicted Saif al-Islam for allegedly ordering the killing of unarmed protesters during the uprising.

Navi Pillay, U.N. High Commissioner for Human Rights, welcomed the capture of Saif al-Islam and Senussi, noting they had both been subject to ICC arrest warrants since June.

The arrests of Gaddafi's son and the former Director of Military Intelligence have enormous significance for the future of justice in Libya. I warmly welcome the announcement by the Prime Minister that Saif Al-Islam Gaddafi will be treated humanely and tried fairly in line with international standards, Pillay said in a statement.

(Reporting by Stephanie Nebehay)