Israeli troops fired tank shells and machine guns Saturday, killing a Palestinian woman and her 13-year-old daughter working in a farm field in the eastern Gaza Strip, Palestinian witnesses and doctors said.

The army said it fired and killed two "suspicious figures" who were bent down and were within 50 yards of the border fence that separates Gaza from Israel. The army said the area is currently off-limits to the Palestinians, adding that Palestinians have attempted to launch attacks in the area seven times in the past month.

Marwan Abu Said, a Palestinian witness and a relative of those shot, said the soldiers fired from three tanks patrolling the border, next to the flat, open field. He said he was not aware of any provocation that prompted the soldiers to fire.

"I tried to run to a safe place on another part of the farm" when the shooting began, he said.

Kamla Abu Said, 42, was killed, along with her daughter, Amna, 13, according to Dr. Ahmed Rabah at the Deir al-Balah hospital. Abu Said's niece, 15, was lightly injured.

Also, Israeli armored personnel carriers and jeeps were spotted moving into the Palestinian town of Bethlehem on Saturday night, Palestinian witnesses said. Army vehicles were also seen moving into the adjacent town of Beit Jalla.

The army declined to comment immediately, though a Palestinian suicide bomber who killed two Israelis in a Wednesday night attack came from the Bethlehem area. Israel has been staging almost daily incursions into West Bank towns in pursuit of suspected militants.

In the northern West Bank, meanwhile, Israeli troops stopped a taxi and arrested a 16-year-old Palestinian boy with an explosives belt strapped to his waist, on an apparent suicide mission, the army said.

On another West Bank road, a Palestinian woman in labor said she was held up by soldiers for 30 minutes at a roadblock, where she gave birth to a baby that died a short while later after she reached a hospital in Bethlehem. The Israeli military disputed the woman's account, saying she was allowed to pass without delay.

Israel says its network of roadblocks, which now surround virtually every Palestinian city and town in the West Bank, are necessary to prevent, or at least limit, the number of Palestinian bomb attacks. Palestinians say the tough restrictions have made normal life impossible, and fail to allow for medical emergencies.

In the incident in the northern West Bank, Israeli troops set up a "surprise roadblock," where they stopped a taxi for a routine check. The four Palestinians inside were asked to set out and lift their shirts -- a now common practice designed to check for would-be bombers wearing explosives.

The 16-year-old was wearing an explosives belt, the army said, prompting soldiers to arrest all four on the road, near the village of Sanur. The belt was removed from the youth and blown up in a controlled explosion, the army said.

Saturday's incident came just three days after another 16-year-old, Issa Bdeir, carried out a suicide bombing that killed two Israelis on Wednesday night just south of Tel Aviv. He was the youngest of the more than 60 bombers who have struck during the current conflict.

Prime Minister Ariel Sharon's office said that the Israeli security forces have "foiled or disrupted" more than 30 attacks by Palestinian militants over the past month. An army offensive in March and April was intended to prevent such attacks, but after a brief lull, the frequency has been increasing again in recent days.

In the other West Bank incident Saturday, Faidea Najajra said she and three relatives left her village of Nahalin, outside of Bethlehem, at 4 a.m. after she went into labor.

Their initial route was blocked by a 10-foot-high earthen barricade placed across the road by the army. The family called a Palestinian ambulance, which came to the other side of the embankment, but medics could not find a way to get Najajra to the other side.

A medic joined Najajra in her car, and while traveling to a crossing point manned by soldiers, she gave birth, she told The Associated Press in a telephone interview.

"When the soldiers saw me, I was screaming and crying," she said. "But the soldiers just looked at me."

She was allowed to pass after 30 minutes, she said. Her newborn was in critical condition when it reached the hospital, and died shortly afterward, said Dr. Jadallah Najar. The exact cause of the baby's death was not clear. Najajra was checked and returned home after about two hours.

An army statement said soldiers allowed her to cross immediately when learning of her condition. The statement also said that she fell off a stretcher as she was being transferred from her car to a Palestinian ambulance.

The military says its policy allows humanitarian cases to pass roadblocks. However, soldiers also regularly conduct extensive checks of ambulances following incidents in which explosives and other weapons were found inside them.

In another development Saturday, Israel's army pulled out of the Tulkarem refugee camp in the West Bank, ending a two-day incursion that uncovered guns and explosives and led to the arrests of about 25 Palestinians suspects, the army said.

The troops went into the camp Friday following several recent attacks inside Israel. Tulkarem is just inside the West Bank and Palestinian militants have launched many attacks from the town.

As the troops moved into the camp Friday, Palestinian militiamen ambushed Israeli soldiers riding on an armored personnel carrier, killing one and wounding two, the army said.

As the soldiers pulled out Saturday, an 11-year-old Palestinian boy was hit by gunfire and wounded, Palestinians said.