UN officials in the Gaza Strip say two children aged five and seven died after an Israeli shell hit a UN school where hundreds of people had taken shelter. It came amid dozens of Israeli air strikes on Gaza.
A spokesman for the UN's relief agency in Gaza called for an inquiry into whether the attack amounted to a war crime. It came as Israel's cabinet prepared to vote on a unilateral ceasefire proposal.
Palestinian health officials in Gaza say nearly 1,200 people have been killed since the conflict began on 27 December, including more than 400 children. Thirteen Israelis, mostly soldiers, have died.
As Gazans continued to mourn their dead, the militant group Hamas said it would ignore any ceasefire if its conditions for Israeli forces to leave the coastal strip and lift the blockade were not met.
Israel's main objective in Operation Cast Lead has been to end Gaza militants' ability to fire rockets at Israel and stop them smuggling weapons through tunnels from Egypt.
But Gaza militants are still firing rockets into southern Israel.
These Ultra-Orthodox Jews are inspecting damage to a synagogue hit by a rocket near the Israeli town of Beersheva.