GAZA/JERUSALEM - An Israeli missile killed at least 11 Palestinian civilians including four children in Gaza on Sunday, medical officials said, apparently an attack on a top militant that brought a three-storey home crashing down.

International pressure for a ceasefire seemed certain to mount in response to the deadliest single incident in five days of Palestinian rocket attacks on Israel and Israeli air strikes on the Gaza Strip.

A Palestinian stone-thrower holds a flag as he stands atop a garbage bin during clashes with Israeli security forces outside Ofer prison near the West Bank city of Ramallah Nov 18, 2012. The clashes broke out following a protest against Israel's military operation in the Gaza Strip. [Photo/Agencies]

Egypt has taken the lead in trying to broker a ceasefire and Israeli media said a delegation from Israel had been to Cairo for talks on ending the fighting, although a government spokesman declined to comment on the matter.

Egyptian President Mohamed Mursi met Hamas political leader Khaled Meshaal and Islamic Jihad's head Ramadan Shallah as part of the mediation efforts, but a presidency statement did not say if they were conclusive.

Izzat Risheq, a close aide to Meshaal, wrote in a Facebook message that Hamas would agree to a ceasefire only after Israel "stops its aggression, ends its policy of targeted assassinations and lifts the blockade of Gaza".

Listing Israel's terms for ceasing fire, Moshe Yaalon, a deputy to the prime minister, wrote on Twitter: "If there is quiet in the south and no rockets and missiles are fired at Israel's citizens, nor terrorist attacks engineered from the Gaza Strip, we will not attack."

Gaza health officials said 72 Palestinians, 21 of them children and several women have been killed in Gaza since Israel's offensive began. Hundreds have been wounded.    

Israel gave off signs of a possible ground invasion of the Hamas-run enclave as the next stage in its offensive, billed as a bid to stop Palestinian rocket fire into the Jewish state. It also spelt out its conditions for a truce.

US President Barack Obama said that while Israel had a right to defend itself against the salvoes, it would be "preferable" to avoid a military thrust into the Gaza Strip, a narrow, densely populated coastal territory. Such an assault would risk high casualties and an international outcry.

A spokesman for the Hamas-run Interior Ministry said 11 people, all of them civilians, were killed when an Israeli missile flattened the home of the Dalu family. Medics said four women and four children were among the dead.

Israel's chief military spokesman said Yihia Abayah, a senior commander of rocket operations in the Gaza Strip, had been the target.

The spokesman, Yoav Mordechai, told Israel's Channel 2 television he did not know whether Abayah was killed, "but the outcome was that there were civilian casualties". He made no direct mention of the destroyed dwelling.

Prime Minister Benjamin Netanyahu said earlier that he had assured world leaders that Israel was doing its utmost to avoid causing civilian casualties in the military showdown with Hamas.

"The massacre of the Dalu family will not pass without punishment," Hamas's armed wing said in a statement.

A Palestinian man and a Palestinian woman walk out of a destroyed house after an Israeli air strike in Gaza City on Nov 18, 2012. [Photo/Xinhua]