Israeli troops clashed with Hamas fighters as they advanced into Gaza tonight in the first ground combat of an eight-day offensive on the Palestinian enclave, witnesses and the Israeli army said.
Columns of tanks backed by helicopters crossed the boundary fence from four directions into the northern Gaza Strip under darkness, a Palestinian witness said.
An Israeli military spokeswoman said the aim was to seize areas from where Hamas was launching rocket attacks on southern Israel.
"The objective is to destroy the Hamas terror infrastructure in the area of operations," Major Avital Leibovitch said. "We are going to take some of the launch areas used by Hamas."
The witness said fighting had broken out in northern Gaza as Hamas fighters took on the Israeli forces. Israeli television showed soldiers in battle gear advancing on foot.
The ground offensive will take many days, the chief military spokesman said.
"This won't be a school outing," Brigadier Avi Benayahu told Israel's Channel Two television. "We are taking about many long days."
Israel has ordered the call-up of tens of thousands of military reservists as part of a ground offensive launched in the Gaza Strip this evening, Prime Minister Ehud Olmert's office said in a statement.
It said that, in accordance with a secret cabinet discussion on Friday, the government ordered the armed forces "to draft the necessary reservists, on a scale of tens of thousands of troops".
Meanwhile,
a senior Hamas official said
Hamas fighters had killed a number of Israeli soldiers in eastern Gaza this evening.
Mohammad Nazzal, who is based in Damascus, reported the deaths on Dubai-based Al Arabiya television. He gave no exact figures.
Earlier, an Israeli air strike on a mosque in Gaza killed 11 Palestinian civilians, including children, and wounded dozens as they prayed, Hamas officials said.
Witnesses said the air strike on the mosque in the town of Beit Lahiya took place as people prayed inside. At least 11 civilians were killed and 50 wounded, Hamas and medical officials said.
Rescuers pulled people from the debris and the bodies of victims lay in pools of blood, the witnesses said.
An Israeli military spokesman had no immediate comment. Israel has targeted mosques previously saying that Hamas had used them as command posts and fire bases.
Hamas kept up its rocket attacks on southern Israel in defiance of international calls for it to halt such actions.
As the Israeli offensive entered its second week, prospects of a ceasefire any time soon looked dim.
"I hope the results of this operation will bring about quiet in the long term. The moment they fire, we will respond with great force," Foreign Minister Tzipi Livni said on Israeli TV.
"It could be that several operations will be needed in this regard."
Today's fighting brings the Palestinian death toll to at least 446, with about 2,050 wounded, in the worst sustained bloodshed in decades of the conflict between Israel and the Palestinians.
Four Israelis have also been killed in cross-border rocket attacks by Hamas and other militant groups.
Israeli artillery cannons shelled the Gaza Strip today, witnesses on both sides of the border said, heralding a possible escalation to a new tactic in more than a week of fighting.
Palestinian witnesses said the artillery cannons caused a large explosion in Gaza City as well as a series of blasts on the nearby frontier with Israel.
Israeli artillery generally fire unguided 155mm shells. If put to sustained use, the weapons could significantly increase the number of civilian casualties from an Israeli air campaign that has killed at least 433 Palestinians.
Israel says it is trying to stop Hamas rocket fire.
Israel has massed ground forces on the Gaza border ahead of any decision to invade the Hamas-ruled territory. One factor which independent analysts said could be holding the army back was concern about Hamas minefields hidden on the frontier
An overnight Israeli air strike killed Abu Zakaria al-Jamal, a senior commander of Hamas's armed wing, today, the Islamist group said.
On Thursday, another Hamas leader, Nizar Rayyan, was killed and most of Hamas's senior officials have gone into hiding to evade assassination attempts by Israel.
Basic foodstuffs in the densely populated zone were running short and fresh water supplies were limited because of damage to the systems, humanitarian agencies said. Hospitals were struggling to cope with the casualties.
At least 20 air strikes targeted Gaza this morning and naval vessels also shelled the area from the Mediterranean coast, witnesses said.
International cease-fire efforts were also gaining momentum.
French president Nicolas Sarkozy is visiting the region next week, and US president George Bush and UN chief Ban Ki-moon both spoke in favour of an internationally monitored truce.
Israel launched the offensive on December 27th in response to intensifying rocket fire by Hamas militants in Gaza. The operation has killed more than 430 Palestinians, including scores of civilians, according to Palestinian and UN counts. Four Israelis have also been killed, and rocket attacks on southern Israel persist.
In the latest attacks, the army struck the homes of two Hamas operatives, saying the buildings were used to store weapons and plan attacks. Hamas outposts, training camps and rocket launching sites also were targeted, it said.
Early today, it dropped leaflets in downtown Gaza City ordering people off the streets.
Later in the day, several air strikes struck the city, killing a night watchman at a Gaza City school. Four people, including a mid-level Hamas commander, died of wounds sustained earlier, Gaza health officials said.
Palestinian militants fired three rockets into southern Israel, causing no injuries.
The Israeli air strikes have badly damaged Gaza’s infrastructure, knocking out power and water in many areas and raising concerns of a looming humanitarian disaster.
Israel briefly opened its border yesterday to allow nearly 300 Palestinians with foreign passports to flee the besieged area. The evacuees told of crippling shortages of water, electricity and medicine.
Maxwell Gaylard, UN humanitarian co-ordinator for the Palestinians Territories, said some 2,000 people have been wounded in the past week and a “significant number” of the dead were women and children. “There is a critical emergency right now in the Gaza Strip,” he said.
Israel denies there is a humanitarian crisis in Gaza and has increased its shipments of goods into Gaza. It says it has confined its attacks to militants while trying to prevent civilian casualties.
While ground troops remained poised to enter Gaza, Israel also has left the door open to a diplomatic solution, saying it would accept a cease-fire if it is enforced by international monitors.
This latest round of violence erupted after the expiration of a six-month cease-fire that was repeatedly marred by sporadic rocket attacks on Israel. A call for international monitors appeared to be gaining steam.
At the United Nations, Ban Ki-moon urged world leaders to intensify efforts to achieve an immediate cease-fire that includes monitors to enforce the truce and possibly protect Palestinian civilians.
In Washington, Mr Bush yesterday branded the rocket fire an “act of terror” and outlined his own condition for a cease-fire in Gaza, saying no peace deal would be acceptable without monitoring to halt the flow of smuggled weapons to terrorist groups.
“The US is leading diplomatic efforts to achieve a meaningful cease-fire that is fully respected,” Mr Bush said in his weekly radio address. “Another one-way cease-fire that leads to rocket attacks on Israel is not acceptable. And promises from Hamas will not suffice.”
Secretary of state Condoleezza Rice continued telephone diplomacy to arrange a truce, but said she had no plans to make an emergency visit to the region.
Palestinian president Mahmoud Abbas and several Arab foreign ministers were flying to New York over the weekend to urge the UN Security Council to adopt an Arab draft resolution that would condemn Israel and demand a halt to its bombing campaign in Gaza.
Mr Abbas, whose forces in Gaza were ousted by Hamas in June 2007, still claims authority over the area.
The council is expected to discuss the draft resolution on Monday. But the US said the draft is “unacceptable” and “unbalanced” because it makes no mention of halting the Hamas rocket attacks.
Agencies