The International Criminal Court prosecutor said on Sunday Saif Al-Islam, the son of Libya's Muammar Gaddafi, had been detained in Libya.

'Saif was captured in Libya,' prosecutor Luis Moreno-Ocampo told Reuters. 'We have confidential information from different sources that we have within Libya confirming this.

'It is very important to make clear there is an obligation to surrender Saif to the ICC in accordance with the Security Council resolution.'

Libyan rebels said earlier that they had detained Saif and Gaddafi's eldest son Mohammed Al-Gaddafi.  

'Gunmen surrounded my house and I am still at home and they are outside,' Mohammed told Al Jazeera TV by telephone from Tripoli. 'They said they will guarantee my safety. They are besieging my house,' he added. The sound of gunfire could be heard in the background. 'Yes, the gunfire is inside my house,' he said before the line was suddenly cut off. 

In June the ICC issued arrest warrants for Gaddafi, his son Saif and Libyan intelligence chief Abdullah Al-Senussi on charges of crimes against humanity after the UN Security Council referred the Libyan situation to the court in February.     

Moreno-Ocampo said the rebel transitional national council in Libya had not yet been in touch with the ICC about the capture of Saif, but the prosecutor said he would be in contact with them on Monday to discuss the next steps. - Reuters