Also Friday, an Israeli motorist was killed and his pregnant wife seriously wounded in a Palestinian shooting attack in the West Bank.
The violence came just hours after an Israeli helicopter in southern Gaza fired missiles, killing a Hamas fugitive as he drove a donkey cart, the fourth lethal airstrike against members of the Islamic militant group in a week.
CBS News Correspondent Robert Berger reports Israeli military sources say the incursions are a warning to the Palestinian Authority: stop the rocket attacks or Israel will reoccupy northern Gaza.
Israel has said all Hamas members involved in attacks on Israelis are marked for death. It intensified its policy of targeted killings after a Hamas suicide bombing killed 21 people on a Jerusalem bus Aug. 19.
Hamas leaders have threatened revenge for the Israeli missile attacks. In the past week, Hamas fired more than a dozen Qassam rockets at Israeli targets, including one that landed Thursday in an industrial zone just south of the coastal city of Ashkelon, the deepest hit yet.
It was only two months ago that Palestinian terror groups declared a truce, reports Berger, but it seems like a distant memory.
Friday's shooting attack killed an Israeli man and seriously wounded his 24-year-old pregnant wife, hospital officials said.
Israel Radio quoted the woman as saying she saw four or five gunmen crouching down by the side of the road, just before they fired at their car. The fetus was not harmed, the radio said.
Palestinian gunmen have repeatedly targeted Jewish settlers traveling on West Bank roadways in three years of fighting. Israel Radio quoted Palestinian sources as saying that PA security forces were searching for the gunmen.
Emergency workers at first thought the couple — who had left their other children with grandparents — had been involved in a traffic accident, because their car was overturned.
In the West Bank town of Jenin, Palestinian gunmen fired on Israeli soldiers manning a lookout in a four-story office building, setting off intense gunbattles, residents said.
An army spokesman confirmed a firefight in Jenin, and said there were no immediate reports of injuries. Eight tanks and armored vehicles, apparently backup, moved in and drove back the gunmen with tank-mounted machine guns before picking up the soldiers from the lookout and moving out of the town, witnesses said.
Also Friday, troops combed the Balata refugee camp on the edge of Nablus, part of a weeklong arrest sweep in the West Bank's largest city.
Swinging sledgehammers, troops broke through walls to move from house to house, a technique used to cut down on soldiers' exposure to possible gunfire. Balata is a stronghold of armed groups.
In their search for militants, soldiers caused considerable damage to several homes, demolishing walls, overturning furniture and breaking household goods, such as tea cups, residents said.
A Palestinian legislator from Balata, Kamal Afghani, was trapped in his home after troops took it over as a lookout, a neighbor said.
In the Gaza Strip, meanwhile, Israeli bulldozers uprooted brush and orchards in Palestinian-controlled areas near the town of Beit Hanoun to deprive those launching rockets of cover, the army and witnesses said.
It was the second such raid in 12 hours and came in response to the rocket fire toward Ashkelon. It marked the first foray into Palestinian-controlled land since Israel withdrew from parts of Gaza in July under the U.S.-backed "road map" peace plan.
Israeli Prime Minister Ariel Sharon said Hamas is trying to hit an Israeli power plant south of Ashkelon. The Qassam rockets, with a range of up to six miles have caused little damage or injury, but Israel considers them a strategic threat. Sharon said he has ordered the military to take all necessary steps to stop the rocket attacks.
As part of the road map, the Palestinians must try to prevent rocket launchings and other attacks and shut down militant groups.
Palestinian police said officers gave chase and exchanged fire with those who launched four rockets Thursday. The Israeli military said the rockets were fired just 15 yards from a Palestinian police post. It was not clear if the post was manned at the time.
The Israeli helicopter strike late Thursday in the southern Gaza town of Khan Younis killed Hamdi Kalakh as he was driving a donkey cart along a residential street. At least three people were reported injured.
Kalakh, 23, was a member of Hamas' military wing. The army said he was responsible for mortar, rocket and bomb attacks on Israeli soldiers and civilians. An army spokesman said the raid thwarted a mortar attack on the nearby Gush Katif Jewish settlement bloc.
Also Thursday, Palestinian authorities opened a new front in a clampdown on militants, freezing 39 bank accounts of nine Islamic charities to investigate whether they channel money to armed groups.
Israel welcomed the decision.
Palestinian officials said they were trying to find a way to monitor the money transfers so that welfare payments made by the charities to thousands of needy Palestinians can resume soon.
Hamas spokesman Abdel Aziz Rantisi denounced Palestinian Prime Minister Mahmoud Abbas for giving in to U.S. and Israeli pressure, while insisting the charities had "nothing to do with Hamas."
President Bush announced last week that the United States is freezing the funds of six senior Hamas figures as well as of five charities that he accused of funding Hamas.