The killing of four armed Palestinian fugitives in a hail of Israeli gunfire is raising new questions about the military's practices during arrest operations in the West Bank.

The Israeli human rights group B'Tselem is calling for a criminal inquiry into the shooting, citing witness accounts claiming the men were summarily executed. B'Tselem says that would violate a ruling by Israel's supreme court that troops must try to take wanted men alive.

Physical evidence, TV footage and testimony reviewed by the Associated Press point to a surprise attack. Even the military does not contend the suspects tried to resist or were urged to surrender.

In the March 12 incident in Bethlehem, Israeli troops riding in a taxi van pulled up behind the fighters’ parked Daihatsu and began shooting immediately, Palestinian witnesses said. TV footage taken minutes later showed two fighters slumped in the back seat. A black sweatshirt worn by a third was punctured by bullets only in the back.

At least 91 bullets hit the car, not counting shots that shattered windows.

The killings have stirred little debate in Israel.

B'Tselem said there have been similar previous cases: since 2004, 300 Palestinians have been killed in what the military defined as arrest operations, including dozens who weren't armed or apparently didn't resist.

"A pattern emerges where it seems that in at least some of the cases, forces operate as if they are on de facto assassination operations, rather than arrest operations," B'Tselem spokeswoman Sarit Michaeli said. She called on the military to investigate all suspicious deaths.

The Israeli military referred to the Bethlehem incident as an arrest raid, but did not say the suspects were asked to surrender. "A special Border Police force identified a number of armed Palestinians inside a car," said an army statement. "The force opened fire, killing the four militants in the vehicle." Commenting on the shooting the following day, Israeli Defence Minister Ehud Barak said: "We demonstrated once again that the state of Israel will continue to pursue and strike all murderers with Jewish blood on their hands." Palestinian President Mahmoud Abbas denounced the shooting as a "crime". Officials in his West Bank-based administration routinely condemn the killings of Palestinians by Israeli troops as "assassinations". The military declined repeated requests for on-the-record comment about West Bank arrest operations, including open-fire rules, saying only that it respects international law and that troops do what they can to ensure their own safety and that of bystanders.

In its 2006 ruling, the supreme court did not ban targeted killings, saying each case should be judged individually, including whether an arrest attempt would pose a serious risk to soldiers.

However, the court said even armed men - the Bethlehem fighters had three automatic rifles in the car - cannot be targeted automatically.

"Among the military means, one must choose the means whose harm to the human rights of the harmed person is smallest," the court said. "Thus, if a terrorist taking a direct part in hostilities can be arrested, interrogated and tried, those are the means which should be employed." Robbie Sabel, a law professor at the Hebrew University of Jerusalem, said different standards apply to the West Bank, which is under full Israeli control, and to Gaza, from which Israeli forces withdrew in 2005.

"The basic rule of international law is that if you are in control of a territory, you arrest people and you have no right to shoot people without trial," said Sabel, a former legal adviser in Israel's foreign ministry.

However, he said the definition of what is a combat situation is often unclear.

The army acknowledges targeted killings in Gaza, where Israeli aircraft routinely strike fighters. Since arrests are not an option, the practice does not go against the supreme court's ruling, legal experts say.

The military said the men killed in Bethlehem - Mohammed Shehadeh, Ahmed Balboul, Issa Marzouk and Imad Kamel - were senior activists in the Islamic Jihad group and were involved in violence since the start of the Palestinian uprising in 2000. Shehadeh, 45, was the Islamic Jihad boss in Bethlehem and was involved in five attacks between 2000 and 2002 that killed three Israelis and wounded 41, Israel said.

Shehadeh's relatives said he admired the Lebanese guerrilla group Hizbollah and even converted from Sunni to Shiite Islam, the faith of Hizbollah supporters.

On March 7, after a Palestinian gunman killed eight Jewish seminary students in Jerusalem, Israeli troops stepped up the search for Shehadeh and demolished the home where his wife and seven children lived.

Five days later, Shehadeh and Balboul, 48, gave an interview to the Iranian television station Al Alam, standing on the rubble of Shehadeh's home. They said Israel only understands the language of force, according to the station's website.

The fighters switched cars frequently, and Balboul's 17-year-old son, Mohammed, said that on that day, they were using the red Daihatsu. He said his father called him just before his death, urging him to study hard for high school finals, and that at one point Shehadeh joined the conversation with the same message.

The shooting took place in Jabal Street, in a residential area of Bethlehem.

Ibrahim Rashed, the 47-year-old owner of a grocery store on the street, said that at about 6:10pm he saw an orange VW minibus - a typical West Bank taxi - pull up. Six Israeli soldiers burst out, including several in uniform, and opened fire, he said. He said the heavy shooting lasted two to three minutes.

Another witness, Mohammed Abu Ahour, said he was in a nearby cellphone shop when the shooting started. He said he ran out and saw Israeli troops firing at the red Daihatsu.

An Israeli in a blue shirt and jeans, who wore a phone headset, ordered him back inside, speaking in Arabic, Abu Ahour said. The witness said he grabbed his terrified wife and two-year-old son who were in a car in front of the Daihatsu, and rushed indoors.

Abu Ahour and Rashed said they saw Kamel, the Daihatsu's driver, lying in the street during the shooting.

The witnesses said they did not see the attacked men use their assault rifles.

Their accounts were marked by several contradictions, including in the versions given to B'Tselem and the AP.

Rashed told the AP the troops opened fire immediately, but he didn't see at first who they were aiming at. He told B'Tselem he saw the troops fire first at the driver who had gotten out of the car, and then at the Daihatsu.

Abu Ahour said the jeans-clad Israeli agent walked to the car after the shooting stopped and fired at the heads of three men inside, then shot Kamel one more time. Hospital emergency doctor Mariam Hmeidat said three of the men suffered massive head wounds, but Balboul did not.

The physical evidence suggests the four were taken by surprise.

Hmeidat said Balboul, the front seat passenger, was hit 10 times in the back of the torso. At Balboul's family home, his 14-year-old son held up the black sweatshirt his father wore at the time of his death, ripped by bullet holes only in the back. In AP Television News footage of the shooting aftermath, Balboul is seen lifeless on the ground beside the Daihatsu, wearing the sweatshirt.

Targeted killings have been part of the military's arsenal since 2000, and many Israelis feel the measures are justified.