The callous slaying of 16 sleeping children and parents in a United Nations-managed school in Gaza takes the three-week-old Israeli assault to new levels of terror. In the middle of the night, Israeli shells repeatedly hit a school in the Jabaliya refugee camp in northern Gaza as it sheltered 3,300 refugees from the violence.

In the face of this terrible act, it is utterly inadequate that all the Israelis say they will do is investigate and apologise if they find that it was an errant fire. The very same day that the shameless Israeli spokesman Mark Regev was mouthing these words, more Israeli shells landed on another school in Gaza — the Beit Lahiya School for Girls. Luckily, no one was killed though eight were injured.

In the past few weeks, United Nations Relief and Works Agency (UNRWA) had told the Israelis about the precise location of the Jabalia Elementary Girls School and had made clear that it housed 3,300 internally displaced people. Nonetheless, the Israelis unleashed hell on the refugees. After visiting the remains of the school, and seeing the body parts of the children and their mothers scattered all over the classrooms, an UNRWA spokesperson broke into tears on Al Jazeera TV.

Israel must be brought to account for its brutal killing of civilians, including women and children. It is well aware that families that had fled Israeli airstrikes were being sheltered in UN-run buildings. UNRWA says that more than 200,000 displaced Palestinians are currently sheltering in 86 UN schools across Gaza. The casual disregard for the consequences of its horrific military actions can only further condemn its actions. The destruction of Gaza’s power plant means that 1.8 million Gazans now have to live without electricity.

World leaders have condemned the Israeli actions, but they now need to add pressure on the Americans to stop treating Israel as beyond reproach. A tough sanctions regime is required for the disgusting and rogue state that has been killing women and children, in an effort to bring it to its senses and show Israelis that their murderous actions do have consequences.