UN General Secretary Ban Ki-moon called for a ceasefire between Israel and Palestinian militants as he headed to the region for talks in Cairo on Monday, DPA reported.
"I strongly urge the parties to cooperate with all efforts led by Egypt to reach an immediate ceasefire," Ban said Sunday.
An Israeli airstrike on a house in Gaza City Sunday killed at least 11 civilians and injured 30 others, the deadliest single incident in a five-day Israeli offensive aimed at curbing Palestinian rocket attacks.
"I am deeply saddened by the reported deaths," Ban said of the airstrike.
"I am also alarmed by the continuing firing of rockets against Israeli towns, which has killed several Israeli civilians. This must stop."
Ban and Egyptian President Mohammed Morsi were to discuss the situation in Gaza and "current regional and international issues," said Amr Rushdi, the spokesman for the Egyptian Foreign Ministry.
Morsi said Saturday his government was in contact with Israel and the Palestinians and suggested there were "some indications that there could be a ceasefire soon."
Hamas spokesman Ghazi Hamad told Al Jazeera the two sides had agreed on 90 per cent of the terms of a ceasefire, but other reports said Hamas had rejected a draft agreement.
Hamas demands the lifting of Israel's naval blockade of Gaza and an Israeli commitment to end targeted killings of its commanders in the strip, the organization's Damascus-based chief Khaled Meshaal told officials in Cairo.
Israeli Foreign Minister Avigdor Lieberman said in Jerusalem that a complete halt to rocket attacks from Gaza was a pre-condition.
Since Israel launched its offensive Wednesday, the military has hit 1,100 targets in the Gaza Strip, while Palestinian militants have launched nearly 1,000 rockets, 540 of which have hit Israel.
The Israeli airstrikes have killed 72 Palestinians, about half of them civilians, and wounded more than 500, Ashraf al-Qedra, the spokesman of the Hamas-run Health Ministry in Gaza, said Sunday.
Three Israelis have been killed by the rockets from Gaza. The Magen David Adom rescue service said it had treated more than 150 Israelis, including patients suffering from shock.
Israel appeared to be changing tactics Sunday, widening the strike targets to include targeting militant leaders and their homes.
Israel's recent call-up of reserve troops, and broadcasting of soldiers training for house-to-house combat operations, have fuelled speculation of a ground invasion.