NABLUS, West Bank -- Israeli troops blasted their way into the homes of three wanted Palestinians on Saturday, killing each in a hail of bullets and straining an uneasy security arrangement with Palestinian President Mahmoud Abbas.
Israel's military said the three, affiliated with a violent offshoot of Abbas' Fatah movement, were targeted for killing an Israeli settler in a roadside ambush earlier in the week and had turned down a chance to surrender.
In the Gaza Strip, three young men approaching Israel's southern border were killed by shots from an Israeli helicopter gunship. Saturday's deaths made it one of the deadliest days in the Israeli-Palestinian conflict since Israel waged war on Gaza's Islamic militant Hamas rulers a year ago.
The violent Nablus raids, after months of relative quiet, embarrassed Western-backed Abbas, whose security forces have been coordinating some of their moves with their Israeli counterparts and share a common foe, Hamas.
At the funeral for the slain men, Abbas' security policy was denounced by thousands of mourners, who chanted: "Why the coordination while we are under the bullets of the army?"
Abbas' prime minister, Salam Fayyad, rushed to Nablus in an apparent attempt at damage control, paying his respects at a large communal wake and condeming Israel. "This attack was a clear assassination, and I believe it is targeting our security and stability," Fayyad said.
Israel did not let Abbas know of the raid in advance, said Maj. Peter Lerner, an Israeli army spokesman.
Saturday's killings put to the test an often strained relationship between Israel's military and Abbas' security.
Since the violent takeover of Gaza by Hamas in 2007, Abbas has gradually strengthened his control in West Bank towns to keep the Islamists there in check.
Palestinian leaders frequently complain that Israel is undermining these efforts by carrying out arrest raids in areas under Palestinian control. Israel counters that while the performance of the Palestinian security forces is improving, its military will step in when necessary.
The target of Saturday's predawn raids were three longtime members of Fatah's violent offshoot, the Al Aqsa Martyrs' Brigades. The army said the three -- Anan Subeh, 36; Ghassan Abu Sharah, 40; and Raed Suragji, 40 -- were involved in Thursday's deadly roadside shooting of an Israeli settler, and that Israeli forces entered Nablus to try to arrest them.
Dozens of Israeli soldiers, some of wearing black masks, poured into Nablus' casbah, or old city, at about 2 a.m. They were backed by sniffer dogs and dozens of jeeps, bulldozers and other military vehicles
The forces surrounded the homes of the three. Lerner, the army major, said all three turned down a chance to surrender. However, relatives of Abu Sharah and Suragji said they were killed without warning. Lerner confirmed that none of the wanted men returned fire, including Subeh, who had two pistols and two assault rifles on him.
Soldiers used explosives to blow open the door of the Abu Sharah's three-story apartment building, said Ghassan Abu Sharah's brother, Jihad. The brother said that when Ghassan came downstairs, one of the soldiers opened fire and killed him.
Troops also used explosives at the home of Raed Suragji, said his wife, Tehani.
She said her husband opened the bedroom door. "Suddenly, shots were fired at us," she said. "He fell down. I started shouting. I held his head in my lap and sat on the ground."
In the third raid, troops ordered everyone to come out of the Subeh home, said Subeh's brother, Jamal. The family evacuated, but Anan Subeh stayed behind.
Lerner said Subeh was hiding in a small crawl space in his home when he was killed. He said soldiers heard him shout "Allahu Akbar," Arabic for God is great.
Asked why soldiers opened fire, Lerner said troops "had to operate under the assumption that they (the suspects) are dangerous."
Subeh had recently been accepted in Israel's amnesty program for Fatah gunmen, according to Nablus' deputy governor, Anan Attireh. Subeh's family said he had also joined the Preventive Security Service, a branch of the Palestinian security forces.
Suragji was released from an Israeli prison in January, after a seven-year term for involvement in shooting attacks. Abu Sharah was also held by Israel in the past, the military said.
The Al Aqsa Martyrs' Brigades carried out scores of shooting attacks and suicide bombings during the second Palestinian uprising, which erupted in 2000. Since then, the militia has been largely dismantled.
In Israel, right-wing critics of Prime Minister Benjamin Netanyahu said his policy of easing travel restrictions in the West Bank was to blame for the shooting attack. Lerner said Israel did not plan to set up new roadblocks.
Also Saturday, an Israeli helicopter gunship killed three Gazans, ages 19 and 20, as they approached the border barrier with Israel. The army said the three were hit after they ignored warning shots.
Relatives of the three had tried to sneak into Israel for work and were not affiliated with political groups.
Israel does not allow Palestinians to approach its border area with Gaza, fearing militants will stage attacks there.
Additional reporting by Diaa Hadid in Gaza City.