Israeli forces launched military operations in the Gaza Strip and the West Bank early Thursday, hours before a Katyusha rocket fired from Gaza crashed down harmlessly near the Israeli city of Ashkelon.

At least nine Palestinians were killed during Israeli tank and helicopter attacks in Gaza, including five members of a family killed near the central city of Khan Younis, Palestinian officials said.

Israeli officials said the Katyusha attack was the deepest strike ever into Israel from Gaza. Katyushas are Soviet-designed rockets with a range of about a dozen miles, roughly twice the maximum distance flown by makeshift Palestinian rockets known as Qassams.

Israeli military officials said the operation in Gaza, which began just after midnight, was intended to counter Palestinian attacks and followed recent rocket strikes. Israeli soldiers also entered the northern West Bank city of Nablus in search of Palestinian fighters. The Katyusha was fired at about 8:30 a.m. Thursday, they said.

"What we've seen today is the beginning of a situation where it isn't just the adjacent communities in the firing line but up to a quarter of a million Israelis," said Israeli government spokesman Mark Regev. "Today's rocket attack represents an escalation, an upgrade, a bigger rocket with a longer range, not something homemade, but something smuggled into Gaza from outside."

Citing concern that more advanced weapons were being brought into Gaza, the Israeli government had one day earlier condemned Egypt's decision to open a border crossing for pilgrims returning from Mecca, Saudi Arabia.

The simultaneous Israeli operations were the most significant offensives in the Palestinian territories in more than two months, residents said.

In Nablus, Palestinian officials said 33 people were injured in clashes, some of them by rubber-coated steel bullets. Gunfire echoed and clouds of tear gas wafted throughout the city during much of the day. Three residents suspected of militant activity were arrested, an Israeli military spokesman said.

The violence occurred as President Bush prepared to visit Israel and the Palestinian territories in an attempt to build momentum toward peace.

"With President Bush coming so soon, one would hope to see positive steps toward the Palestinian people, but instead we see the opposite," said Jamal al-Muhaisen, governor of Nablus. While Nablus has long been considered a stronghold of militant groups launching attacks on Israel, the Palestinian Authority has intensified policing efforts there in recent months.

"I regard this incursion as an attempt to destroy our security plan, which was working," Muhaisen said.

Bush's visit is timed to build on November peace talks in Annapolis, Md. Those meetings included Israeli and Palestinian officials, but not representatives of the armed Islamic movement Hamas, which controls Gaza.

[Hamas said one Palestinian fighter was killed Friday in a clash with Israeli troops near the northern Gaza town of Beit Hanoun, the Reuters news agency reported from Gaza City.]

The attack in Bani Suhailah, east of Khan Younis, killed Karima Fayad, her daughter Asma, 20, and sons Sami, 28, and Ahmed, 31, when tank shells struck their home. Israeli officials said the men had been shooting at Israeli forces before taking refuge in the house. Blood soaked the walls of the two-story home and olive trees in the back yard.

As the bodies were removed in white coffins, neighbors and relatives wailed and shouted, "There is no God but Allah!"

"I didn't get to say goodbye," cried Maria Fayad, who lost her stepmother and three siblings in the attack. Another Fayad relative died in clashes nearby. "How can they all be gone in one minute?"