The situation in northern Mozambique is worse than thought, a UN spokesman says, days after Cyclone Kenneth ravaged the country.
The system struck the Africa nation on Thursday with winds of 220km/h (140mph) which flattened whole villages.
Around 700,000 people are now thought to be at risk in the area as torrential rains continue.
Pemba, regional capital of Cabo Delgado state, has experienced more than 2m (6.5ft) of rain and flooding.
Office for the Co-ordination of Humanitarian Affairs (Ocha) spokesman Saviano Abreu said the situation in the towns of Macomia and Quissanga was critical, adding that there were also worries for the cut-off island of Ibo.
Waves up to 4m high are expected, and aid agencies fear rains will worsen.