Washington said it was "deeply troubled" by the "humanitarian impact" of Israel's bombing of the power plant in the Gaza Strip.
State Department spokeswoman Jennifer Psaki said yesterday: "We're deeply troubled by the humanitarian impact of reduced electricity in Gaza, particularly for emergency services, and urge all parties to respect the civilian nature of these facilities."
She noted that she was aware of Israel's shelling of a hospital in the Gaza Strip, and had received reports about the deaths of children due to shelling.
She stressed the need for "all parties to respect the civilian nature of schools and medical facilities. These facilities, which serve as shelters for many of those fleeing the conflict, must be treated as inviolable and off-limits from military use and targeting by all sides.
"As the violence continues, we are concerned about the safety and security of civilians on both sides, and we continue to urge all parties to do all they can to protect civilians."
Israel began its war on Gaza on July 7 in an operation it calls "Protective Edge", several weeks into the offensive it began a ground offensive into the Strip.
Some 53 Israeli soldiers and three civilians have been killed during the assault. The Izz Ad-Din Al-Qassam Brigades, the armed wing of Hamas, said it had killed 110 Israeli soldiers and captured another.
Some 1,255 Palestinians have been killed by Israeli raids on the Strip which have also left 7,100 injured, the majority of which are women and children.
Earlier, deputy chairman of the Energy Authority in Gaza Fathi Al-Sheikh Khalil said Israel had targeted the main fuel tank to the power station in central Gaza, causing the station to stop working completely.