BEIRA, Mozambique (AP) — A week after Cyclone Idai lashed southern Africa, flooding still raged Thursday as torrential rains caused a dam to overflow in Zimbabwe, threatening riverside populations. The confirmed death toll in Zimbabwe, neighbouring Mozambique and Malawi surpassed 500, with hundreds more feared dead in towns and villages that were completely submerged.

Aid agencies and several government entities continued to step up their deployments, with helicopters in short supply for hundreds of thousands of people displaced by the cyclone.

Spokesman Herve Verhoosel of the World Food Programme told reporters in Geneva of the “alarming news” that the Marowanyati dam in Zimbabwe was hit by heavy rains overnight, putting populations in the region at risk.

Zimbabwe’s defence minister said more than 120 bodies had been washed into neighbouring Mozambique, where residents there buried them, and more bodies were still being recovered in rivers, raising the official death toll in the country to at least 259.

“Most of the bodies were washed into Mozambique and because they were in a really bad state, they could not keep the bodies,” Defence Minister Oppah Muchinguri said, speaking in the eastern city of Mutare. “So they ended up burying them.”

Mozambique’s environment minister, Celso Correia, who is heading up the government response team, said in Beira yesteray that the confirmed death toll in his country was 242, with at least 142 injured and an untold number still missing.

“Don’t create panic,” Correia urged other government officials as more updates on the devastation trickled in. He said some 65,000 people had been saved by rescue workers who plucked them from rooftops and trees, and 182,000 had been affected by the flooding.

“Obviously all numbers are preliminary. … They are changing every day, every moment,” Correia said, adding that the most worrying issue now was health, with cholera a major concern. He said a much bigger rescue and recovery mission must be launched in the region of some 350,000 people, where many remain marooned on islands created by the floodwaters.

It will be days before Mozambique’s inundated plains drain toward the Indian Ocean and even longer before the full scale of the disaster is known. Mozambican President Filipe Nyusi has said as many as 1,000 people could have died in his country alone, but even that huge number is likely to pale in comparison to reality, aid workers said.

“Now that the water is receding, we fear that we will see even more,” than 1,000, as far more bodies are discovered, the secretary-general of the International Federation of Red Cross and Red Crescent Societies, Elhadj As Sy, told The Associated Press.

Homes, villages and entire towns were submerged across central Mozambique, where flooding created a muddy inland ocean 30 miles (50 kilometres) wide. The UN food aid agency said 400,000 people were displaced and “in urgent need of life-saving assistance” in Mozambique’s coastal city of Beira and flooded areas along the Pungue and Buzi rivers.

The persistent rains eased in some areas yesterday and floodwaters began to recede in Beira, the worst-hit city, and in the countryside, according to a Mozambican Government report.

“Yesterday, 910 people were rescued by the humanitarian community,” said Caroline Haga of the International Federation of the Red Cross in Beira. She said 210 were rescued by five helicopters and 700 were saved by boats.

Aid groups were continuing to work non-stop to rescue families desperately clinging to tree branches and rooftops for safety from the surging waters.

“A family saw their brick house swept away from them. When they went to another house for safety, the roof collapsed,” Machiel Pouw, Save the Children’s response team leader in Mozambique, said in a statement. “Another family fled for safety in a tree. There are tens of thousands of heartbreaking stories like this, lives shattered over the past days.”

In Malawi, where at least 56 people died, the Government reported more than 920,000 people were displaced by the floods, the WFP said.

In Zimbabwe, 90 per cent of the district of Chimanimani — the country’s hardest-hit — was significantly damaged, the agency said, estimating that 200,000 people would need food assistance over the next three months.

Zimbabwe’s President Emmerson Mnangagwa declared two days of mourning starting tomorrow for the victims, saying he witnessed “unmitigated despair” during a tour of the area on Wednesday. Government officials say as many as 350 Zimbabweans may have died in the flooding.

Aid has been slow to reach affected villagers due to collapsed infrastructure, although the military has been handing out small packets of cooking oil, maize meal and beans.