U.N. says Israel violated international law, after shells hit school in Gaza

United Nations officials accused Israel of violating international law after artillery shells slammed into a school overflowing with evacuees Wednesday, an attack that Palestinian and U.N. officials said killed at least 20 people and wounded dozens as they slept.

It was one of the worst mass-casualty incidents of the three-week war. The building was the sixth U.N. school in the Gaza Strip to be rocked by explosions during the conflict.

Israeli officials said they were trying to determine who was responsible for the bloodshed. In past incidents, the Israeli military...