Libya's floods, which killed thousands in the city of Derna, also displaced more than 43,000 people, the International Organization for Migration said Thursday.
A tsunami-sized flash flood broke through two ageing river dams upstream from the city after heavy rains lashed the area on September 10. It razed entire neighbourhoods, sweeping untold thousands into the Mediterranean Sea.
The official death toll stands at more than 3,300 -- but the eventual count is expected to be far higher, with international aid groups giving estimates of up to 10,000 people missing.
"An estimated 43,059 individuals have been displaced by the floods in northeastern Libya," the IOM said, adding that a "lack of water supply is reportedly driving many displaced out of Derna" to other areas.
"Urgent needs include food, drinking water and mental health and psychosocial support," it said.
Mobile and internet services were restored Thursday after a two-day disruption, following protests Monday that saw angry residents blame the authorities for the high death toll.
The national telecom company said communications were down as a result of "a rupture in the optical fibre" link to Derna, but some internet users and analysts charged there had been a deliberate "blackout".
Earlier this week, the United Nations warned that disease outbreaks could bring "a second devastating crisis" to the flood-hit areas.
Local officials, aid agencies and the World Health Organization "are concerned about the risk of disease outbreak, particularly from contaminated water and the lack of sanitation", the UN said.
Libya's disease control centre warned that mains water in the disaster zone is polluted and called on residents not to use it.