CAIRO U.N. Secretary General Ban Ki-moon said on Wednesday there were "many details to work out" before a ceasefire could be reached to end the conflict between Israel and Palestinian militants in the Gaza Strip.
"I am particularly concerned about the spiral of violence at the time of intense efforts to reach a ceasefire in Gaza and Israel," Ban said.
Speaking after a meeting with Egyptian President Mohamed Mursi, whose country is trying to forge a truce, he said: "We all know there are many details to work out. But while that happens civilians continue to die."
Ban condemned an attack on a bus in Tel Aviv that wounded 15 people and said it "makes it all the more urgent to reach an immediate ceasefire".
Ban met Mursi in Cairo after meeting Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas.