An attack on a UN-run school in Gaza today has claimed lives among the UN staff, Secretary General Ban Ki-moon said.
"Many have been killed -- including women and children, as well as UN staff," Ban said in a statement.
Gaza's emergency services said 15 people were killed and more than 200 injured when an Israeli shell slammed into the school run by the UN agency for Palestinian refugees (UNRWA).
Ban said he was "appalled" by the news and "strongly condemned" the attack on the school in Beit Hanun, in the northern Gaza Strip.
"Today's attack underscores the imperative for the killing to stop -- and to stop now," he said in the statement released in Iraq, his latest stop on a tour to try to secure a ceasefire in Gaza.
UN spokesman Farhan Haq separately said officials were trying to determine the number of casualties among UN staff and stressed that it had not been established who had attacked the school.
The Israeli army said it would investigate the circumstances surrounding the school attack.
