President Filipe Nyusi on Wednesday declared three days of national mourning after days of torrential rain and flooding killed more than 200 people and left a trail of destruction across southeast Africa.

A report, published by the World Food Programme (WFP) on Tuesday, said that the emergency crisis situation in the wake of the devastation caused by the tropical cyclone in south-east Africa "is getting bigger by the hour."

Five days after the storm made landfall in Mozambique, causing widespread damage and flooding, at least 1,000 people are feared dead there alone, the report said.

Victims are trapped on rooftops awaiting rescue operations, while, houses, roads, communication networks, bridges and crops have been washed away in the floods across Mozambique, Malawi and Zimbabwe, the UN report said.

Bulldozers and debris cleaners struggled to clear up muddied roads in parts of the Chipinge and Chimanimani districts in Zimbabwe. Rescue helicopters have been deployed to carry out the rescue operation in a school which got buried under a mudslide.

"We are talking about a massive disaster right now where hundreds of thousands -in the millions of people - (are) potentially affected," said Jens Laerke from the UN Office for the Coordination of Humanitarian Affairs (OCHA).

"We need all the logistical support that we can possibly get," Laerke added.

Aid access is "the biggest challenge", a WFP spokesperson was quoted as saying.

The aid agency further noted that the rescuers, who flew over the area inundated since the weekend, reported of "inland oceans extending for miles and miles".

According to the report, the WFP aimed at providing support to around 600,000 people affected by the cyclone in Mozambique, while, providing food assistance to approximately 650,000 victims in Malawi.

"This is the worst humanitarian crisis in Mozambique's recent history," Al Jazeera quoted Jamie LeSueur from International Federation of Red Cross and Red Crescent Societies in Nairobi, as saying.

Meanwhile, India has become the first international responder to the Cyclone Idai in Mozambique, by diverting three naval ships and delivering the first batch of Humanitarian Assistance and Disaster Relief (HADR) stores including food, medicines and clothing to the Maputo's defence authorities.

The Indian Navy is also planning to set up medical camps and provide food, water, blankets and other necessary relief items, as required by the local authorities.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)