Gaza Strip ? Gaza City was plunged into darkness Sunday after Israel blocked the shipment of fuel that powers its only electrical plant in retaliation for persistent rocket attacks by Gaza militants.

The power cut sent already beleaguered Gazans to stock up on food and batteries in anticipation of dark, cold days ahead. Gaza officials warned the move would cause a health catastrophe while a U.N. agency and human rights groups condemned Israel.

“We have the choice to either cut electricity on babies in the maternity ward or heart surgery patients or stop operating rooms,” Gaza Health Ministry official Dr. Moaiya Hassanain said.

Four hours after the blackout, Hamas claimed that five patients died because of the cutoff of electricity in hospitals. The claim could not be confirmed.

Late Sunday, Israel carried out two airstrikes in Gaza City, Palestinian security officials said. The Israeli military confirmed both attacks in which a militant linked to Islamic Jihad was killed.

Israel justified the fuel cutoff because of continuous rocket attacks by Gaza militants.