Via BBC:
An attack that killed 10 people at a UN-run Gaza school was a “moral outrage and a criminal act”, UN Secretary General Ban Ki-moon has said.
It constituted a “gross violation of international law”, Mr Ban said.
State Department spokeswoman Jen Psaki said the US was appalled by the “disgraceful” shelling.
Israel has declared a humanitarian ceasefire in most of Gaza for seven hours on Monday.
Brig Gen Yoav Mordechai said the ceasefire would apply to all of the Gaza Strip except eastern Rafah from 10:00 (07:00 GMT) to 19:00.
Sunday’s blast hit the entrance of the school, which is sheltering thousands displaced by the conflict. Israel denies firing into the school.