Israel retaliated Thursday for a deadly suicide bombing in a crowded market with a series of airstrikes and arrests that Israeli officials described as the first stage of a sustained military effort against the radical Palestinian faction Islamic Jihad.

In the early evening, an Israeli aircraft fired on a car traveling in the Jabalya refugee camp in the northern Gaza Strip, according to military officials and witnesses. Hospital officials said eight Palestinians were killed, including Shadi Mahanna, the top Islamic Jihad commander in northern Gaza, and his deputy, Mohammed Qandeel. A Palestinian Health Ministry official and Islamic Jihad leaders said the remaining dead were civilians, including a 15-year-old boy.

The operations began after Prime Minister Ariel Sharon, facing heavy criticism in some quarters after a suicide bomber killed five Israelis on Wednesday at a market in the coastal city of Hadera, north of Tel Aviv, said that the Palestinian Authority was "not taking any serious steps in -- and is not serious about -- the struggle against terrorism." He vowed that Israel would take up the task in a "wide-ranging and continuous" military campaign. Sharon made his comments during a meeting here with Russian Foreign Minister Sergei Lavrov.

Sharon also said he would not meet with Palestinian leader Mahmoud Abbas until Palestinian authorities moved against armed groups in their territories. The two men had announced plans to hold a summit, the first since Israel's withdrawal from the Gaza Strip last month, no later than the first week in November.

Palestinian leaders warned that the Israeli strikes would dim prospects for a new peace process. "We have condemned the Hadera attack," Prime Minister Ahmed Qureia told reporters. "It doesn't serve our people's interests, but at the same time we condemn the Israeli aggression. The aggression does not bring calm."

The Bush administration, Russia and other foreign governments had hoped that the end of Israel's 38-year presence in the Gaza Strip would revive peace talks. But Islamic Jihad and the larger Palestinian radical group Hamas have used Gaza's northern border regions to launch rockets into southern Israel. They have said such attacks were in retaliation for Israeli military actions, including assassinations of members of their groups.

Secretary of State Condoleezza Rice urged Abbas in a phone call Thursday to crack down on the armed groups.

As Israelis gathered by the hundreds to bury those killed in the suicide bombing, the military operation unfolded. The chief target was Islamic Jihad, which asserted responsibility for the Hadera attack.

Israeli forces closed off the West Bank, which it has occupied since the 1967 Middle East war, and sealed two crossing points between Gaza and Israel.

Israeli military officials said 17 Palestinians had been arrested in the West Bank during the day, most of them Islamic Jihad members. In Qabatiya, the bomber's home town in the northern West Bank, Israeli soldiers detained three Islamic Jihad members and a man they described only as "wanted."

Witnesses said the man was the father of Hassan Abu Zayd, the 20-year-old who blew himself up outside a popular falafel restaurant in Hadera Wednesday afternoon. Islamic Jihad officials said the attack was retaliation for Israel's killing Monday of Luay Saadi, 26, the group's military leader in the West Bank.

In the largest show of ground force, more than 30 Israeli army jeeps backed by helicopters entered the city of Jenin in the northern West Bank around 3 p.m. Israeli military officials said the soldiers arrested four Islamic Jihad members, including the group's local leader, Abed Halim Izzadin, before withdrawing.

In an interview at his Jenin apartment in June, Izzadin described himself as a moderate within the organization. He said he had spent 11 years in Israeli prisons, but belonged to a faction in the political wing of the group that supported participation in Palestinian elections.

"It is only natural that there will be a response from the Islamic Jihad, if not here then elsewhere," Izzadin said at the time, referring to Israel's targeting of its members. "If I were to be assassinated, it would bring more resistance."

During the day, Israeli soldiers also arrested three members of Hamas, which like Islamic Jihad refuses to recognize Israel's right to exist.

The military operation came during an escalating diplomatic confrontation between Israel and Iran, which supports Islamic Jihad. President Mahmoud Ahmadinejad told a student audience Wednesday that Israel was a "disgraceful blot" that should be "wiped off the map."

In the June interview, Izzadin acknowledged Iran's support for the organization. But he said that Israeli officials had overstated the influence of Iran, which is led by Shiite clerics. Islamic Jihad emerged in the early 1980s from Egypt's Muslim Brotherhood, an organization of Sunni Muslims. "Maybe in the beginning there was more support from Iran," Izzadin said. "I can tell you now that the scope of the material assistance from Iran is less than 10 percent" of what the group raises.

Staff writer Glenn Kessler in Washington contributed to this report.

Palestinians remove what is left of the car of Islamic Jihad's northern Gaza commander, Shadi Mahanna, after he and his deputy were killed by an airstrike.