ON THE ISRAEL-GAZA BORDER — Israeli tanks and ground troops moved swiftly Sunday to seize large sections of Gaza, encircling its largest city and cutting the narrow strip of land in two in what military officials called a "real war" on the militant Islamic group Hamas.
On the first full day of ground operations following an eight-day air assault, Israeli infantry units, backed by firepower from Apache helicopters and Navy warships, swept into the Hamas-controlled coastal territory in the early morning hours and began going house-to-house in search of Palestinian militants, witnesses said.
Seventy Palestinians were killed, including 21 children, and another 140 people injured, according to Gaza medical officials.
While heavy fighting and airstrikes echoed across northern Gaza, terrified residents hunkered down in their homes as relief agencies described a deepening humanitarian crisis. The Israeli military campaign has knocked out power and running water to most of the strip's 1.5 million residents, and all of Gaza's hospitals are running on generators that "are close to collapse," the U.N. said.
World leaders expressed dismay at the escalation in fighting, but no roadmap to a quick truce emerged.
Israeli Prime Minister Ehud Olmert acknowledged that the ground operation opened a new and much more dangerous phase in the war, but said that it was necessary to cripple Hamas's infrastructure and to stop militants from firing thousands of crude rockets from Gaza into Israeli territory.
"This operation was unavoidable," Olmert told his Cabinet.
Defying the ground invasion, Gaza militants fired another 40 rockets into southern Israel on Sunday, military officials said. Residents scrambled for shelter but no serious injuries were reported.
The Bush administration has backed Israel's use of force and blocked approval of a U.N. Security Council statement that would have called for an immediate cease-fire. The administration has said that Hamas must take the first step toward a cease-fire.
Hamas leaders vowed to turn Gaza into a "graveyard" for Israeli soldiers, but casualties on the first day were not as heavy as many expected. One Israeli soldier was killed and another severely injured, officials said, while 28 others suffered relatively minor injuries.
The incursion into densely populated Gaza marks Israel's biggest military operation there in years. As they surrounded Gaza City, Israeli forces exchanged fire with militants armed with mortars and remote-controlled bombs, officials said. Israeli forces pushed nearly to the territory's Mediterranean coastline, eyewitnesses said, effectively severing the northern third of Gaza off from the south.
The ground troops were backed by ongoing Israeli air attacks that struck 45 Hamas targets overnight, including rocket-launching pads, and by Navy ships that fired on the headquarters of Hamas's intelligence headquarters in Gaza City, military officials said.
From fields and forests along the Gaza border, Israeli artillery units fired round after round at distant targets inside Gaza. In some parts of Gaza City, residents were forced to flee their homes when militants took up positions in apartment buildings.
An estimated 13,000 Palestinians have been forced from their homes and ambulances have been unable to respond to the crush of emergency calls from residents in northern Gaza.
More than 500 Palestinians have been killed since the start of the Israeli operation eight days ago, Gaza health officials said, and approximately 2,500 have been injured. The U.N. estimates that at least 20 percent of the Palestinian casualties are civilians. Five Israelis have been killed.
"This is beyond a humanitarian crisis; it's a humanitarian catastrophe," said John Ging, the head of the United Nations refugee agency in the Gaza Strip. "People are trapped, traumatized and terrorized."
The U.N. estimates that 70 percent of Gaza residents have no access to running water and Israeli human rights groups say three-quarters of the residents now have no power.
The prolonged blackouts have forced hospitals to rely on straining generators to keep intensive care units running. Gaza's only power plant has been shut down for nearly a week because Israel has not transferred critical industrial fuel needed to run the generators.
Since launching the operation nine days ago, Israel has allowed only 400
truckloads of aid into Gaza, which Ging said was "wholly inadequate." Before
the crisis began, nearly 500 truckloads of supplies were being shipped into
Gaza each day.
Pro-Gaza demonstrations continued in some Arab cities, and in Beirut, Lebanon, police used tear gas and water hoses to deter about 250 protestors who were trying to reach the U.S. Embassy, news agencies reported.
Despite the protests and calls from many world leaders for a halt to the fighting, Israeli leaders indicated that the operation would not end quickly.
"We want to have a significant and lasting change in the security situation on our southern border," said Brig. Gen. Ilan Tal, an Israeli military spokesman. "It will take the time it will take."
Israel has declared large sections of its border with Gaza to be a closed military zone where tanks and troops are preparing to expand the ground offensive. Analysts said the operation could soon spread to southern Gaza, along Israel's border with Egypt, as Israel tries to destroy the network of tunnels that militants use to smuggle weapons.
Israel has already rejected calls for a 48-hour truce and Hamas has vowed to continue firing rockets until Israel reopens its borders to allow food and relief supplies into Gaza.
French President Nicolas Sarkozy was due in the region Monday to try and jump-start talks on a possible cease-fire. He was expected to meet with Israeli leaders and with Palestinian Authority President Mahmoud Abbas, whose secular Fatah party was driven out of Gaza by Hamas in 2007 and has become increasingly estranged from the militant group.
"Right now it may be that the operation on the ground has more momentum than the diplomatic operation," said Nicolas Pelham, an analyst with the International Crisis Group research agency.
Nissenbaum reported from the Israeli-Gaza border and Bengali from Jerusalem. Special correspondent Ahmed Abu Hamda contributed from Gaza.
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