MAPUTO/HARARE — Mozambique started three days of national mourning on Wednesday after powerful cyclone winds and flooding killed hundreds of people and left a massive trail of destruction across swathes of southeast Africa.

Cylone Idai, which hit Mozambique's port city of Beira on Thursday before moving inland, brought winds of up to 105 mph that flattened buildings and put the lives of millions of people at risk.

Mozambique's President Filipe Nyusi said in a televised statement on Tuesday that the cyclone had killed more than 200 people in Mozambique but that more bodies were still being discovered.

In neighboring Zimbabwe, the official death count stands at 98 but is likely to grow as hundreds are still missing.

Rescue crews are still struggling to reach victims, while aid groups say many survivors are trapped in remote areas, surrounded by wrecked roads and submerged villages.

"Challenges remain in terms of the search and rescue of thousands of people, including children," UNICEF said. It estimated that 260,000 children were at risk in Mozambique. The Red Cross has said at least 400,000 people have been made homeless in central Mozambique alone.

Beira, a low-lying coastal city of 500,000 people, is home to Mozambique's second-largest port and serves as a gateway to landlocked countries in the region.

Local media reported that there were food and fuel shortages in central Mozambique because Beira was cut off by road.

In eastern Zimbabwe, grieving families are rushing to bury their dead because the cyclone has knocked out power supplies and stopped mortuaries from functioning. Zimbabwe's Grain Millers Association said 100 trucks carrying wheat destined for Zimbabwe were stuck in Beira.

Residents comb the earth in search of bodies in Chimanimani, Mozambique, after Cyclone Idai swept through the area. Zinyange Auntony / AFP - Getty Images

Studies of satellite images suggested 1.7 million people were in the path of the cyclone in Mozambique and another 920,000 affected in Malawi, said Herve Verhoosel, senior spokesman at the U.N World Food Programme said Tuesday. He gave no figures for Zimbabwe.

Heavy rains preceded the cyclone, compounding the problems.

"If the worst fears are realized ... then we can say that it is one of the worst weather-related disasters, tropical-cyclone-related disasters in the southern hemisphere," said Clare Nullis of the U.N. World Meteorological Organization.

The European Union announced on Tuesday an initial emergency aid package of $3.97 million to Mozambique, Malawi and Zimbabwe for emergency shelters, hygiene, sanitation and health care. Britain has also pledged $7.96 million in aid.