March 23 (UPI) -- The death toll in Mozambique from Cyclone Idai grew to more than 400 Saturday, a number that is expected to grow higher amid fears rivers could burst their banks again, U.N. officials said.
The overall death toll from the storm is estimated to be about 700, including deaths in Zimbabwe and Malawi. Some officials believe the final death toll could be in the thousands once all bodies are accounted for and a list of the missing is compiled.
United Nations Office for the Coordination of Humanitarian Affairs coordinator Sebastian Rhodes Stampa said officials may never be able to account for all the dead.
"It will be heartbreaking once we know the full extent," he said. "Most of the bodies were likely swept out to sea and may or may not ever wash ashore."
The OCHA said there are further risks that the Buzi and Zambezi rivers could burst their banks.
Cyclone Idai formed nearly two weeks ago in the Mozambique Channel before striking the coast of Mozambique March 15 and moving over Zimbabwe. Heavy rains caused landslides in Zimbabwe before floodwaters flowed down into the plains of Mozambique.
The U.N. International Children's Emergency Fund said some 1.8 million people have been affected by the cyclone in Mozambique, 900,000 of them children.
"The situation will get worse before it gets better," UNICEF Executive Director Henrietta Fore said after visiting the town of Beira. "Aid agencies are barely beginning to see the scale of the damage. Entire villages have been submerged, buildings have been flattened, and schools and healthcare centers have been destroyed."
Officials are concerned waterborne diseases could proliferate throughout the region, including cholera, malaria and diarrhea.