At least five people have been killed after a sewage treatment pool collapsed and flooded a village in the Gaza Strip, Palestinian officials said.
The earth wall gave way in the village of Umm al-Naser in northern Gaza, submerging at least 25 houses.
Some 25 people are reported hurt but many more are unaccounted for. The village has a population of 3,000.
Residents said the flood was like a "tsunami" and Interior Minister Hani al-Qawasmeh rushed to the scene.
Angry residents crowded around Mr Qawasmeh when he came to inspect the damage.
Reports said shots were fired, forcing the minister and his entourage to flee the village, although it is unclear where the gunfire came from.
Health ministry officials said the dead included two toddlers and a 70-year-old woman.
Militants from the Hamas group and rescuers were helping to find those thought buried in the sewage.
The Israeli army said it would also help - although it is not yet known whether Palestinian officials have accepted the offer.
Village council head Ziad Abu Farya told the Associated Press news agency the scene was "our tsunami".
One villager, Amina Afif, said: "We lost everything, everything was covered by the flood. It's a disaster."
Fadel Kawash, head of the Palestinian Water Authority, told AP several sewage projects, including one in the village, had been halted after international funding dried up in the wake of the election victory of Hamas in January last year.
"We had a project to treat sewage in north Gaza, it was worked on for two years," he said.
"We built a pressure pipeline and pumping station but it was stopped after... troubles began."
Hamas also blamed the flood on the withdrawal of foreign aid.
But Stuart Shepherd, the UN's humanitarian aid officer in Gaza, said the Umm al-Naser plant had not been affected by the aid boycott, noting there had long been warnings about the plant.
A UN report in 2004 had warned that the sewage facility was at its maximum capacity, and flooding was inevitable unless a new waste treatment plant was constructed.
Mr Shepherd said foreign investment had been secured to build the treatment plant, but construction had not gone ahead because of security risks in the area.
The facility, built in the 1970s to serve a population of 50,000, was serving 190,000 people by 2004, according to the UN.
The head of Gaza's environmental authority, Yusuf Abdel Safir, estimated that a pool of four million cubic metres of water had built up.
He told the BBC that the PWA had built a small lagoon to deal with rising pressure in the main pool.
"This new lagoon has been constructed just three months ago to release this pressure. This lagoon has collapsed today because of the pressure," he said.