Chimanimani, Zimbabwe — 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, neighboring Mozambique and Malawi surpassed 500, with hundreds more feared dead in towns and villages that were completely submerged.

Aid agencies and several governments 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 Program 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.

A child is transported on a fridge during floods after Cyclone Idai, in Buzi, outside Beira, Mozambique, on March 21, 2019. Reuters

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

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"Most of the bodies were washed into Mozambique and because they were in a really bad state, they could not keep the bodies," Defense 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 the coastal city of Beira Thursday evening 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 "bigger-size rescue operation" must be launched in the region of some 350,000 people, where many remain marooned on islands created by the floodwaters.

The death toll was sure to rise. It will be days before Mozambique's inundated plains drain toward the Indian Ocean and even longer before the full scale of the devastation is known. Mozambican President Filipe Nyusi has estimated that 1,000 people could have been killed in his country alone, while Zimbabwean officials say some 350 people may have died there. In Malawi, at least 56 people were killed.

Homes, villages and entire towns were submerged across central Mozambique, where flooding created a muddy inland ocean 30 miles (50 kilometers) wide. The U.N. food aid agency said 400,000 people were displaced and "in urgent need of life-saving assistance" in Beira, the worst-hit city, and flooded areas along the Pungue and Buzi rivers.

Beira is Mozambique's fourth-largest city and a port that sits on the mouth of the River Pungwe, BBC News reports. Its geography, with parts of it lying below sea level, makes it vulnerable to extreme weather.

The persistent rains lifted in some areas on Thursday, and floodwaters began to recede in Beira 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."

It will be days before Mozambique's inundated plains drain toward the Indian Ocean and even longer before the full scale of the devastation is known.

WFP said Malawi's government had reported more than 920,000 people in the country were affected by the floods. The agency said Idai had had a "limited impact" on Malawi, and projected that the number of affected people will decline as they return home.

In Zimbabwe, 90 percent 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.

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.

In Chimanimani, Philemon Dada began rebuilding his life in what was once a picturesque town. With a machete and a hoe, he salvaged poles from the mud to construct a hut to shelter his family, a first step in what he sees as a long and backbreaking journey to rebuild a life shattered by Cyclone Idai.

He is one of many villagers trying to pick up the pieces in Chimanimani after losing homes, livestock and, in many instances, family members. Some have been taken in by neighbors and others are sheltering with church pastors.

"I can say I am a bit lucky. My wife and son are still here with me but for everything else, I have to start from scratch," he said.

Dada had a few food items handed out by the Zimbabwe military, but he knew that wouldn't last long and he was eager to start growing crops again. Like many people here, he survives on agriculture.

"My bean crop was ready for harvesting before the cyclone, the maize was close. I am back to zero," he said.

He is particularly pained by his two prized bulls that did the heavy work of drawing the plow for his field. They died in the floods.

"It may take a year, maybe even more years just to get back on my feet," he said.