Tank fire has killed at least 15 Palestinians sheltering at a school in a Gaza refugee camp, the UN says.
Witnesses at the UN-run Abu Hussein school, where thousands were taking refuge, said walls had been destroyed.
Israel, which has accused the militant group Hamas of using schools as bases to launch rockets, said it was investigating the reports. At least 1,200 Palestinians and 55 Israelis have been killed since Israel launched its offensive on July 8.
