The United Nations is urging the international community to provide immediate support for flood-stricken Libya.
UN Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Martin Griffiths spoke at a news conference in Geneva on Friday.
Griffiths described the disaster in Libya "shocking" and "unimaginable in its consequences."
He said people in affected areas need food and shelter as well as equipment to rescue survivors trapped in mud and damaged buildings.
He added that a medical system should be established as a cholera outbreak is feared.
Floods triggered by heavy rain on Monday caused damage to vast areas in eastern Libya, disrupting transportation and communication. The true extent of the damage is not yet known, and rescue and aid efforts are facing difficulties.
The mayor of the badly-hit city of Derna told NHK that about 8,000 people have so far been confirmed dead and that the number could eventually exceed 20,000.