Israel is facing the strongest international condemnation yet from friends and allies after a school used as a shelter was attacked, killing 10 people.

The destruction in Gaza's Shijaiyah neighbourhood.

The destruction in Gaza’s Shijaiyah neighbourhood.

The US State Department called the incident “disgraceful” while UN Secretary-General Ban Ki-Moon called it a “moral outrage and a criminal act”.

British Foreign Secretary Phillip Hammond echoed those thoughts, saying he was “appalled at the reports”. He added: “It is tragic that there are further losses of life in a place which is being used as a shelter.”

The widespread backlash prompted Israel to announce a unilateral 7-hour “humanitarian ceasefire” on Monday, which Gaza-based officials said it immediately broke when it bombed a house, killing three people.

The UN chief said that those responsible for the shelling must be held accountable. The IDF said it was targeting three Islamic Jihad members on motorcycles riding in the vicinity school and did not target or hit the school itself.

More than 1,800 people have now been killed in the Gaza offensive, with more that 3,250 rockets fired toward Israel from Gaza.

Palestinian factions including Hamas, Fatah and Islamic Jihad were meanwhile meeting in Cairo to agree their collective conditions and demands for a ceasefire.

According to a report in Al Jazeera, they include a full withdrawal of Israeli troops from Gaza, an end to Israel’s blockade of Gaza, building an airport and seaport, an expansion of fishing rights and the release of prisoners not released when the peace talks broke down in April.

However, the list does not include the demands on Egypt to open the Rafah crossing.