Kalandia Checkpoint, West Bank ? A West Bank assailant detonated a large bomb near a busy Israeli military checkpoint Wednesday, killing two Palestinian men and wounding 16 people, mostly civilians, in an attack that prompted rare Palestinian complaints about militants responsible for scores of bombings in the past four years.

The Al Aqsa Martyrs’ Brigades, a violent group that has carried out scores of attacks on Israelis, claimed responsibility for the attack but apologized for the Palestinian casualties. The 16 wounded included 10 Palestinians and six Israeli border policemen.

Al Aqsa said the intended target was Jerusalem and the assailant hastily set off the 44 pounds of explosives by remote control near the Kalandia checkpoint north of the city when he felt Israeli security forces were closing in on him.

The blast went off between two cars, sending a cloud of black smoke into the air as a large crowd of Palestinians was waiting to cross Kalandia. Thousands cross the checkpoint every day, and the bomber’s apparent disregard for Palestinian civilians touched off an emotional confrontation in a West Bank emergency room where some of the wounded were being treated.

Zakiyah Abu Sneineh, whose 60-year-old husband, Salah, died in the blast, refused to acknowledge that he was killed by Palestinians. “Arabs couldn’t have killed him, only Israelis,” she said, sobbing in the emergency room of a Ramallah hospital. In an adjacent room, her 6-year-old grandson Mahdi, who was critically wounded in the blast, was fighting for his life.

The Abu Sneinehs were in their car, waiting in a line of vehicles, when the blast went off.

A Palestinian man hurt in the attack said it was too early to judge the militants. “I don’t want to blame them,” said Rateb Abu Fkhaideh, 47, who had a leg injury.

His comments angered several Palestinians in the emergency room. “Why are you defending them (the militants)?” 35-year-old Nader Omar asked Abu Fkhaideh. “They are wrong. We should raise our voice against them. These guys don’t use their minds.” Two others nodded in agreement.

In four years of Israeli-Palestinian fighting, support for the militants in Palestinian society has remained high, despite the hardships from Israeli retaliation for scores of bombings and shootings. From time to time, criticism of the militants is voiced. However, while Palestinians may complain in private, they rarely express their misgivings openly.

Elsewhere, a senior U.N. official told the U.N. Security Council on Wednesday that both Israel and the Palestinians were violating their international legal obligations and undermining prospects for peace.

Undersecretary-General for Political Affairs Kieran Prendergast said Israel had an obligation to protect Palestinian life and not to destroy property unless there was an absolute military need. He said the Palestinian Authority had obligations “to protect Israeli civilians from attacks emanating from territories in its control.”

Since the outbreak of fighting, 3,049 people have been killed on the Palestinian side and 970 on the Israeli side. Several Palestinians have been killed and scores wounded in attacks by militants, often while spending time in Israeli malls, cafes or outdoor market, or while riding on buses.