Bin Laden's voice heard on hand-held radio

US forces have reportedly detected the voice of Osama bin Laden on hand-held radios around Tora Bora.

According to reports, unnamed US officials have said he was giving orders to his al-Qaida troops.

Electronic monitoring is being carried out by special forces troops on the ground and by spy planes

and satellites.

Officials say the voice has been positively matched to known recordings of bin Laden.

US officials say there are a lot of al-Qaida in the mountains between two parallel valleys, Agam and Wazir, leading to Jalalabad in the north and the Pakistan border in the south.

Bin Laden is moving between the valleys with an entourage of troops, according to the reports.