Israeli troops battled Hamas fighters in major cities of overcrowded Gaza on Tuesday as they moved further into southern Gaza and demanded Hamas be prevented from rearming as a main condition for a ceasefire in an 11-day-old conflict in which at least 580 Palestinians have been killed.
At least 12 members of the same extended family, including seven children, were killed in an Israeli air strike on their house in Gaza City, medics and witnesses said Tuesday afternoon.
The bodies of the Daya family's seven children aged one to 12 years, three women and two men were pulled from the rubble of a house in Gaza City's southern neighbourhood of Zeitun, which was hit by two Israeli missiles overnight, according to witnesses.
Israeli strikes hit two separate schools run by the United Nations in the Gaza Strip, killing at least five Palestinians, U.N. officials said.
Palestinian medics, reporting on casualties before the deaths at the U.N. school, said 20 Palestinian civilians were killed on Tuesday, including 10 people who were hit by naval shells along the beach in the central Gaza Strip.
Israeli tanks firing cannons and backed by helicopter gunships rolled into the southern city of Khan Yunis in the pre-dawn hours, to be met by return fire from Hamas and other forces, witnesses said.
The incursion came as Israeli infantry and Hamas fighters exchanged fire inside Gaza City and at the edges of Deir al-Balah and al-Bureij in the centre of the territory, witnesses and medics said.
Rockets into Israel
Despite the relentless air, ground and naval assault on their stronghold launched to stop rockets, Hamas continued to fire into Israel.
One projectile slammed 45 kilometers (28 miles), the deepest yet inside the Jewish state, wounding a 3-year-old girl, the army said.
Three others landed elsewhere without causing injuries.
Israeli Prime Minister Ehud Olmert vowed that the campaign would continue until Israel completely wiped out Hamas's ability to fire rockets into Israel.
"The results of the operation must be... that Hamas must not only stop firing but must no longer be able to fire," he was quoted as saying.
"We cannot accept a compromise that will allow Hamas to fire in two months against Israeli towns."
Gaza militants have continued to fire rockets into Israel despite the massive offensive, with three civilians and one soldier killed by the projectiles since Israel unleashed its "Operation Cast Lead" on Hamas on Dec. 27 with a massive air bombardment of Gaza, and poured in thousands of ground troops a week later.
The army said on Tuesday an Israeli paratroop officer was killed overnight in northern Gaza, indicating he may have been killed by friendly fire.
The death brings to five the number of Israeli soldiers killed since the army poured ground troops into the Hamas stronghold on Saturday.
Israel's military, describing Monday's shelling of an Israeli force by an Israeli tank, said soldiers from the Golani infantry brigade were hit while occupying a building in the northern Gaza Strip leaving three killed and 24 injured.
The brigade's commander, a colonel, was among the wounded.
The International Committee of the Red Cross said people were dying because ambulances could not reach them amid the fighting.
A spokesman for Prime Minister Ehud Olmert, spelling out a crucial condition for a ceasefire, said Israel would not agree to a truce unless it included provisions to prevent Hamas from rearming.
Hamas, which seized the Gaza Strip from the rival Fatah group in 2007 and has smuggled in weapons through tunnels running under the border with Egypt, used the previous six-month ceasefire brokered by Cairo to double the range of its rockets from 20 km (12 km) to 40 km (24 miles), spokesman Mark Regev said
Hamas has demanded a lifting of Israel's blockade of Gaza in any future ceasefire.
The fighting in one of the world's most densely-populated places where minors make up a large chunk of the 1.5 million population has claimed dozens of civilian lives.
Israeli officials have insisted they are doing all to prevent civilian casualties and have blamed Hamas for operating from civilian centers.
Hamas, which has ruled Gaza since seizing the densely populated coastal enclave in June 2007 from forces loyal to Abbas, has refused to back down.
"Victory is coming," its senior leader in Gaza, Mahmud Zahar, said in a television broadcast.
Israel faces intense international pressure to ease the suffering of the aid-dependent 1.5 million Gaza population, which has no power or water supplies and finding food is a daily struggle.
At least 580 Palestinians have been killed, nearly 100 of them children, and more than 2,700 wounded since the beginning of hostilities, according to Gaza medics.