The UN’s top humanitarian official said on Friday that Libya required equipment to find people stuck in muck and ruined houses following floods that killed thousands, as well as primary health care to avert a cholera outbreak among survivors.

“Priority areas are shelter, food, and key primary medical care because of the fear of cholera and a lack of clean water,” Martin Griffiths said at a United Nations briefing in Geneva.

He said the U.N. humanitarian office had sent a disaster coordination team of 15 people to Libya who had been redeployed from Morocco, which suffered an earthquake last week.

Swathes of Derna, the centrepoint of the destruction in the country’s east, were obliterated by flooding on Sunday night, bringing down whole buildings while families were asleep.

Griffiths said that a suggestion by the mayor of Derna to create a maritime corridor to deliver aid could be a viable option given that the city is on the Mediterranean Sea.

“You still keep coming in from the land, you’re finding the people who are fleeing south, fleeing south from Derna, towards aid, away from the cities, so you need to support them as well,” he said.

“But certainly, adding the maritime option makes complete sense.”