GAZA/JERUSALEM (Reuters) - An Israeli missilekilled at least 11 Palestinian civilians includingfour children in Gaza on Sunday, medical officialssaid, apparently an attack on a top militant thatbrought a three-storey home crashing down.International pressure for a ceasefire seemedcertain to mount in response to the deadliestsingle incident in five days of Palestinian rocketattacks on Israel and Israeli air strikes on the GazaStrip.Egypt has taken the lead in trying to broker aceasefire and Israeli media said a delegation fromIsrael had been to Cairo for talks on ending thefighting, although a government spokesmandeclined to comment on the matter.Egyptian President Mohamed Mursi met Hamaspolitical leader Khaled Meshaal and Islamic Jihad'shead Ramadan Shallah as part of the mediationefforts, but a presidency statement did not say ifthey were conclusive.Izzat Risheq, a close aide to Meshaal, wrote in aFacebook message that Hamas would agree to aceasefire only after Israel "stops its aggression,ends its policy of targeted assassinations and liftsthe blockade of Gaza".Listing Israel's terms for ceasing fire, MosheYaalon, a deputy to the prime minister, wrote onTwitter: "If there is quiet in the south and norockets and missiles are fired at Israel's citizens,nor terrorist attacks engineered from the GazaStrip, we will not attack."Gaza health officials said 72 Palestinians , 21 ofthem children and several women have beenkilled in Gaza since Israel's offensive began.Hundreds have been wounded.Israel gave off signs of a possible ground invasionof the Hamas-run enclave as the next stage in itsoffensive, billed as a bid to stop Palestinian rocketfire into the Jewish state. It also spelt out itsconditions for a truce.U.S. President Barack Obama said that whileIsrael had a right to defend itself against thesalvoes, it would be "preferable" to avoid amilitary thrust into the Gaza Strip, a narrow,densely populated coastal territory. Such anassault would risk high casualties and aninternational outcry.A spokesman for the Hamas-run Interior Ministrysaid 11 people, all of them civilians, were killedwhen an Israeli missile flattened the home of theDalu family. Medics said four women and fourchildren were among the dead.Israel's chief military spokesman said YihiaAbayah, a senior commander of rocket operationsin the Gaza Strip, had been the target.The spokesman, Yoav Mordechai, told Israel'sChannel 2 television he did not know whetherAbayah was killed, "but the outcome was thatthere were civilian casualties". He made no directmention of the destroyed dwelling.Prime Minister Benjamin Netanyahu said earlierthat he had assured world leaders that Israel wasdoing its utmost to avoid causing civiliancasualties in the military showdown with Hamas."The massacre of the Dalu family will not passwithout punishment," Hamas's armed wing saidin a statement.VIOLENCEIn other air raids on Sunday, two Gaza City mediabuildings were hit, witnesses said. Eightjournalists were wounded and facilities belongingto Hamas's Al-Aqsa TV as well as Britain's SkyNews were damaged.An employee of the Beirut-based al Qudstelevision station lost his leg in the attack, localmedics said.The Israeli military said the strike targeted arooftop "transmission antenna used by Hamas tocarry out terror activity", and that journalists inthe building had effectively been used as humanshields by Gaza's rulers.For their part, Gaza militants launched dozens ofrockets into Israel and targeted its commercialcapital, Tel Aviv, for a fourth day, once in themorning and another after dark.Israel's "Iron Dome" missile shield shot down allthree rockets, but falling debris from the daytimeinterception hit a car, which caught fire. Its driverwas not hurt.In scenes recalling Israel's 2008-2009 winterinvasion of Gaza, tanks, artillery and infantrymassed in field encampments along the sandy,fenced-off border. Military convoys moved onroads in the area newly closed to civilian traffic.Netanyahu said Israel was ready to widen itsoffensive."We are exacting a heavy price from Hamas andthe terrorist organisations and the Israel DefenceForces are prepared for a significant expansion ofthe operation," he said at a cabinet meeting,giving no further details.The Israeli military said 544 rockets fired fromGaza have hit Israel since Wednesday, killingthree civilians and wounding dozens. Some 302were intercepted and 99 failed to reach Israel andlanded inside the Gaza Strip, it added.Israel's declared goal is to deplete Gaza arsenalsand force the Islamist Hamas to stop rocket firethat has bedevilled Israeli border towns for yearsand is now displaying greater range, putting TelAviv and Jerusalem in the crosshairs.Israel withdrew settlers from Gaza in 2005 andtwo years later Hamas took control of theimpoverished enclave, which the Israelis havekept under blockade.OBAMA CAUTIONS AGAINST GROUND CAMPAIGNAt a news conference during a visit to the Thaicapital Bangkok, Obama said Israel has "everyright to expect that it does not have missiles firedinto its territory".He added: "If this can be accomplished without aramping up of military activity in Gaza that ispreferable. That's not just preferable for thepeople of Gaza, it's also preferable for Israelisbecause if Israeli troops are in Gaza they're muchmore at risk of incurring fatalities or beingwounded," he said.Obama said he had been in regular contact withEgyptian and Turkish leaders - to secure theirmediation in bringing about a halt to rocketbarrages by Hamas and other Islamist militants."We're going to have to see what kind of progresswe can make in the next 24, 36, 48 hours," headded.Diplomatic efforts continued on Sunday whenFrench Foreign Minister Laurent Fabius met Israeliofficials and Palestinian President Mahmoud Abbasin the West Bank."It is absolutely necessary that we move urgentlytowards a ceasefire, and that's where France canbe useful," Fabius told French television, addingthat war must be avoided.U.N. Secretary-General Ban Ki-moon will be inEgypt on Monday for talks with Mursi, the foreignministry in Cairo said. U.N. diplomats earlier saidBan was expected in Israel and Egypt this weekto push for an end to the fighting.Israel's operation has so far drawn Westernsupport for what U.S. and European leaders havecalled its right to self-defence, but there was alsoa growing number of appeals from them to seekan end to the hostilities.