International pressure for a cease-fire is growing, but the United States is still giving Israel room to maneuver.
In remarks prepared for his weekly radio address, President Bush said that the United States will support a cease-fire only if monitors are sent to stop weapons from being smuggled into Gaza.
"The United States is leading diplomatic efforts to achieve a meaningful cease-fire that is fully respected," Bush said in his first public statements on the conflict. "Another one-way cease-fire that leads to rocket attacks on Israel is not acceptable. And promises from Hamas will not suffice. There must be monitoring mechanisms in place to help ensure that smuggling of weapons to terrorist groups in Gaza comes to an end."
While the current administration is actively working to resolve the crisis, Secretary of State Condoleezza Rice kept the responsibility for a cease-fire on Hamas, saying the group "has held the people of Gaza hostage."
"It is obvious that the cease-fire should take place as soon as possible, but we need a cease-fire that is durable and sustainable," Rice said.
Since the fighting began a week ago, at least 430 Palestinians and four Israelis have been killed.
As Israel continues to build forces for a possible invasion of the Gaza Strip, Hamas' exiled leader said that the group was prepared to resist.
In a televised address from Damascus, Syria, Khaled Meshaal threatened to kidnap Israeli soldiers if there is a ground invasion.
"If you commit a foolish act by raiding Gaza, who knows, we may have a second or a third or a fourth Shalit," Meshaal said, apparently referring to kidnapped Israeli soldier Gilad Shalit, whom Hamas has held for more than two years.
Meanwhile, a fresh barrage of Israeli missiles crashed into Gaza today aimed at the homes of key Hamas operatives, but among the victims were four Palestinian children.
Israel broadened its list of targets on the seventh day of its Gaza offensive. One day after it killed well known Hamas leader Nizar Rayyan and his family, including 11 children, it blasted the homes of more than a dozen Hamas officials.
Israeli officials said many of the targeted homes received warning calls shortly before they were bombed, a practice the Israelis called "roof knocking." But in the rubble of one bombing in the town of Khan Younes were the bodies of three young children, according to medical sources in Gaza. They said a fourth child died during an attack in Gaza City.
The grim collateral damage of the Israeli air war included two other children who also died today of wounds suffered earlier in the week, the sources said.
The most prominent Hamas leader targeted in today's raids was Imad Aqel, one of the group's top military commanders. A house thought to be his was destroyed, but there was no word on Aqel's whereabouts. Many of Hamas' leaders went into hiding when the Israeli attacks began last Saturday.
While Israeli missiles missed Aqel, they killed two young brothers, who live on the same street. Other wounded children were rushed to the hospital. At least 50 children have been killed since the attacks began.
Israeli missiles also struck a mosque in Jabaliya, the seventh mosque bombed since Saturday.
In a statement, the Israeli military said, "The mosque was used as a storage site for a large amount of Grad missiles and additional weaponry. The strike set off a lengthy series of secondary explosions and a large fire, caused by the munitions stockpiled in the mosque." Grad rockets are longer-range weapons in Hamas' arsenal.
Throughout the day Israeli television ran video of the airstrike and enormous post-strike explosions in Jabaliya.
Sources in Gaza say that the death toll has now climbed to 422, with 2,070 wounded. The rising body count has not swayed Israel's determination to end the threat of Hamas rockets or Washington's support for the operation, at least publicly.
White House spokesman Gordon Johndroe echoed that sentiment, saying: "We're not seeing Hamas stop its rocket attacks and, you know, that's something we're going to need to see them do."
Johndroe hinted at a prolonged Israeli offensive. "They've signaled that this is not an operation that they're going to stop right now because they have to protect their people," he said.
Johndroe declined to say whether the White House expected or supported a ground attack by Israel. "I don't want to speak to an operation that has not taken place, that may or may not take place," he said.
The United Nations' World Food Program said today that it would begin an emergency distribution of bread in Gaza because a food shortage is developing.
"The current situation in Gaza is appalling and many basic food items are no longer available on the market," said WFP representative Christine van Nieuwenhuyse.
Palestinian leader Mahmoud Abbas is heading to New York Monday when Arab countries hope to present a motion at the United Nations Security Council condemning Israel for its bombing of Gaza and calling for a cease-fire. Abbas and his Fatah Party govern in the West Bank, but have no authority in Gaza which is run by Hamas.
The growing number of civilian dead, especially children, prompted Israelis officials today to reveal that Rayyan and his family had received a "roof knocking" alert, giving them time to escape before the Israeli jets dropped a 2,000 pound bomb on the house.
Rayyan reportedly ignored the warning, and subsequently killed in the explosion were Rayyan and 15 members of his family -- his four wives, six sons and five daughters
An official who did not want to be identified said Israeli intelligence knew Rayyan and his large family were in the house. The intelligence called the home and told the occupants they had minutes to leave.
The Israeli official said that surveillance aircraft spotted several people leaving the home and the decision to hit it was made. The decision to destroy the house had to be made quickly because the Israelis had strong suspicions that it was being used as a storage site for weapons and they didn't want to give those inside enough time to move the weapons, the official said.
Jonathan Peled, Israeli Embassy spokesman in Washington, said "the multiple secondary explosions that resulted from the attack confirm that Rayyan's house functioned as a weapons storage facility." Peled said the house also served as a communications center and had an escape tunnel beneath it for Hamas terrorists.
Peled called Rayyan "a senior leader for Hamas who called for renewed suicide attacks against Israel. He was personally involved in past suicide missions, including a double suicide attack at the Ashdod port in March 2004 that murdered 10 people. He even sent his own son on a suicide mission, when Ibrahim Nizar blew himself up in Elei Sinai, murdering two Israelis in June 2001."
Palestinians living in Jabaliya, a slum of 87,000 people in northern Gaza, viewed Rayyan as a Kalashnikov-slinging hero who led Hamas fighters there two years ago when Israeli ground forces moved into the area to push back rocket launch sites.
Rayyan also gained popularity by thumbing his nose at Israeli threats of bombing by encouraging people to stay in their homes and in some cases to go to the roofs to show pilots that they would kill women and children. The tactic forced Israel to call off some strikes.
Some Gazans say that in the last year Rayyan appeared to be sidelined as a major player in Hamas. His activity in the group had diminished and he was devoting more time to his religious studies.
Despite the Israeli attacks, Hamas continues to launch rockets aimed at Israeli towns. So far today at least 25 Hamas rockets have been fired at Israeli cities near Gaza. Since Saturday, four Israelis have died in rocket attacks and 72 have been wounded, including two women in Ashkelon.
In the West Bank, thousands of Palestinians have taken to the street including Hamas supporters, who were banned from holding demonstrations during the last 18 months by the rival Palestinian Fatah organization that rules the West Bank. In the town of Hebron, Hamas supporters threw stones and shoes at Palestinian security officials.
Clashes between Palestinians and Israeli police were also reported in a few areas in Jerusalem, outside the Old City.
Sami Zyara reported from Gaza; Nasser Atta, Matthew McGarry, Bruno Nota and Dana Savir reported from Jerusalem; and Kirit Radia from Washington, D.C. Reuters contributed to this report.