Israeli warplanes returned to the attack on the Gaza Strip before first light on Saturday as leaders of the Jewish state weighed a unilateral ceasefire.

Political sources said a decision could come by evening. The government of Prime Minister Ehud Olmert may declare a halt to the three-week-old offensive without concluding any deal with Hamas-led militants who control Gaza, they said.

Ending a night of sporadic gunfire, the roar of jet aircraft around10 p.m. ET was followed by heavy explosions flashing over points to the south and north of the city of Gaza.

The Israeli army said 50 targets here hit, including 16 tunnels, two mosques from which troops were fired on, three bunkers, eight rocket-launching pads and six mined areas including a booby-trapped building.

A spokeswoman had no immediate comment on a report that two civilians were killed near a school. About 45,000 Gazans are sheltering in U.N.-run schools in the enclave.

More than 1,150 Palestinians have been killed and 5,100 wounded since Israel began attacking Gaza with an air blitz on December 27, then moved in with ground forces a week later.

A large majority of the dead were civilians. Ten Israeli soldiers have died in the fighting and three Israeli civilians have been killed by rockets fired from Gaza.

Olmert summoned his security cabinet for Saturday night to decide on a ceasefire, which could come less than 72 hours before the inauguration of Barack Obama as U.S. president.

Israel may wish to avoid casting any cloud on a historic day for its main ally. Support at home for its offensive has been almost total but most the world wants to end the bloodshed.

An overwhelming majority of states at the U.N. General Assembly called on Friday for an immediate, durable ceasefire in what diplomats described as a cohesive, moderate world viewpoint that would strengthen Egyptian mediating efforts.

The unending pain of Gaza civilians is also harrowing. Israeli television on Friday broadcast the desperate cries for help of a Palestinian doctor who called an Israeli TV contact to say his children had just been killed.

"I want to know why they were killed, who gave the order?" Izz el-Deen Aboul Aishhe cried in a voice shaking with emotion. Troops later helped the family's survivors.

Dismissing notions of "proportionate" response, Israel struck on December 27 with a "shock and awe" night of bombing and has used devastating firepower every day since to stop militants firing rockets at Israel civilians in southern cities.

The rockets have tapered off but not ceased. On Friday at least 15 rockets and mortar shells hit Israel, wounding five.

Israeli strikes on Friday killed 30 Gazans, including an Islamic Jihad commander. Tank fire hit the home of a Hamas militant, killing his wife and five children, but not him.

Israeli sources said Egyptian mediation with Hamas was not progressing. But Israel may believe it has now "taught Hamas a lesson," as Olmert described its aim, and prefer to simply stop rather than give Hamas the satisfaction of a negotiated deal.

Foreign Minister Tzipi Livni, hoping to succeed Olmert when Israel votes on February 11, said on Friday that an end to the war "doesn't have to be in agreement with Hamas but rather in arrangements against Hamas."

She was in Washington sealing a pact for U.S. help to ensure Hamas no longer smuggles arms to Gaza via Egypt.

She said Hamas still holds kidnapped soldier Gilad Shalit, a cause celebre in Israel, whom Hamas considers a trump card.

Exiled Hamas leader Khaled Meshaal on Friday called Israel's ceasefire terms unacceptable. Demanding an end to the punitive Israeli blockade of Gaza, he said Hamas would fight on.

Hamas negotiators, however, were due to meet the Egyptians on Saturday to discuss Israel's response to their conditions.

Hamas offers a one-year, renew