NABLUS (Ma'an) -- Sewage from Israeli settlements near Salfit in the northern West Bank is flowing into nearby Palestinian communities and causing serious disease, a health ministry official said Tuesday.

Speaking at an environmental conference in Salfit, the head of Salfit's ministry of health office said the situation had become "intolerable" for communities affected by disease from the sewage, including cases of cholera.

Waste from factories in an industrial zone inside an Israeli settlement is threatening Salfit's agriculture, the Salfit governor said.

Barqan settlement, near Salfit's Qana Valley, has the largest industrial complex of the Israeli settlements in the West Bank, Gov. Isam Abu Bakr said.

He warned that the dumping of waste in 11 sites surrounding Salfit had become a major cause of cancer in the area.

All Israeli settlements built in the occupied West Bank and East Jerusalem are illegal under international law.