An earthen embankment around a sewage reservoir collapsed Tuesday, spewing a river of waste and mud that killed at least five people and forced residents to flee from a village in the northern Gaza Strip, officials said.
A local Palestinian official blamed the disaster on shoddy infrastructure and UN officials said they had been warning of a catastrophe for more than two years.
A 70-year-old woman, two toddlers and a teenage girl died in the sudden flood, and 25 people were injured, said Dr. Muawiya Hassanin of the Palestinian Health Ministry.
Other reports put the death toll as high as 10. The Jerusalem Post said at least 30 people were also missing. At least eight people were injured, and at least 25 houses were completely submerged.
Palestinian emergency workers poled between the houses on flat-bottomed boats and chickens fled their coops to perch high on power lines.
A senior army officer told the Israeli news Web site Ynet that the Palestinians had not asked for Israeli assistance with containing the spill. The officer said Israel had offered to assist in evacuating flood victims to Israeli hospitals and to transfer medical equipment to the Palestinian Authority.
The Palestinians said that, for now, they were able to deal with the flooding on their own, reported the Post.
Fadel Kawash, head of the Palestinian Water Authority, said that the level of sewage in the cesspool had increased over the past few days, creeping up the earth embankments around the pool until one collapsed, "causing the sewage to pour toward the village."
Ziad Abu Farya, head of the village council, described the scene as "our tsunami."
Rescue crews and gunmen from the militant Muslim group Hamas rushed to the area to search for people feared buried under the slide of sewage and mud. Most residents fled or were evacuated. Three children left on a cart pulled by a donkey, heading toward the nearby town of Beit Lahiya.
Angry residents drove reporters out of the area and mobbed government officials who arrived at the scene. When Interior Minister Hani Kawasmeh arrived to survey the damage, his bodyguards had to fire in the air to disperse the crowd.
"We lost everything. Everything was covered by the flood. It's a disaster," said Amina Afif, 65, whose small shack was destroyed.
A 2004 United Nations report warned that the sewage facility was at its maximum capacity and flooding was inevitable unless a new waste treatment plant was constructed. It said that even without overflowing, the effluent lake posed a serious health hazard, providing a breeding ground for mosquitoes and waterborne diseases.
Stuart Shepard, of the UN Office for the Coordination of Humanitarian Affairs, said the wave of waste released Tuesday sent the health risks even higher.
"It is an extremely serious situation," he said.
Shepard said that since the report was published, international funding for a new plant had been secured but construction had not been able to go ahead because of the high security risks in the area.
Umm Naser is about 300 yards from the border with Israel, in an area where Palestinians have frequently launched rockets into Israel and Israeli artillery and aircraft have fired back.
Hamas spokesman Fawzi Barhoum blamed international "sanctions against Palestinians, including Gaza and the West Bank" for the condition of Gaza's infrastructure. Most foreign donors froze aid to the Palestinian government after Hamas swept to power in a 2006 general election, but Shepard said the Umm Naser project had not been affected by the boycott.