More than 1,000 people could be dead after a powerful storm and floods in Mozambique, the president said on Monday.
Eighty-four deaths have been confirmed in Mozambique after Cyclone Idai, which also left a trail of death and destruction across Zimbabwe and Malawi.
Vast areas are flooded, roads destroyed and communications wiped out.
President Filipe Nyusi said he flew over the affected region where two rivers had overflowed. Villages had disappeared and bodies were floating in the water, he said.
"Everything indicates that we can register more than 1,000 deaths," Mr Nyusi told state broadcaster Radio Mocambique.
The cyclone also killed 98 people in Zimbabwe where more than 200 are missing, the government said on Monday.
The death toll in Malawi from heavy rains and floods was 56 as of last week.
Caroline Haga, a senior International Federation of the Red Cross official in Beira, Mozambique, said the situation could be far worse in the surrounding areas, which remained completely cut off by road and where homes were not as sturdy.
Mr Nyusi flew over areas that were otherwise unaccessible, some of which had been hit by flooding before Cyclone Idai.
In Beira, home to 500,000 people, a large dam had burst, further complicating rescue work.
Large areas of land were completely submerged and in some streets people waded through knee-high water around piles of mangled metal and other debris.
In the early hours of Monday morning rescuers steered dinghies through reeds and trees, where some people perched on branches to escape the water.
Meanwhile, others were struggling to reach people in Zimbabwe's Chimanimani district, cut off from the rest of the country by torrential rains and winds of up to 170kph, which swept away roads, homes and bridges, and knocked out power and telecom lines.
Zimbabwe's treasury has released $18 million (Dh66.1m) to rebuild roads and bridges, and provide water, sanitation and electricity.
Families began burying the dead but the death toll is expected to rise.
Many people had been sleeping in the mountains since Friday, after their homes were flattened by rockfalls and mudslides or washed away by rain.
The government has declared a state of disaster in areas affected by the storm. Zimbabwe, a country of 15 million people, was already suffering a severe drought that has wilted crops.
In February 2000, Cyclone Eline hit Mozambique when it was already devastated by its worst floods in three decades.
It killed 350 people and made 650,000 homeless across southern Africa, also hitting Zimbabwe.