Hundreds of thousands of civilians in the Gaza Strip are on the brink of a humanitarian crisis after the kidnapping of an Israeli soldier and Israel's response, the top UN humanitarian official said Thursday. Israel's bombing of a power plant Tuesday night cut 40 percent of power to the Gaza Strip and threatens to leave many of its 1.4 million civilians without water, Jan Egeland said. Egeland called the power plant bombing a violation of humanitarian law that brought needless suffering to innocent civilians. More than 130 wells can be powered by fuel, but diesel supplies could run out in three days because Gaza's borders have been sealed, he said. Egeland was equally critical of the Palestinian side, saying the kidnapping of the soldier on Sunday "was the worst possible thing at the worst possible time." No deaths or serious injuries have been reported in any of the attacks since the operation began. But Egeland said 10 of 16 international staff with the U.N. Relief and Works Agency in the Gaza Strip had to withdraw because of security concerns.