Sixty prominent Palestinian officials and intellectuals urged the public Thursday not to retaliate for Israel's assassination of Hamas' founder, saying it would ignite a new round of bloodshed that would only hurt Palestinian aspirations for independence.

The half-page advertisement in the PLO's Al-Ayyam newspaper called on Palestinians to lay down their arms and turn to peaceful means of protest to end Israel's occupation of the West Bank and Gaza Strip.

The ad reflected growing sentiment among many Palestinian leaders and intellectuals that military struggle is not helping the Palestinian cause. Thousands of Palestinians have died during 3½ years of fighting with Israel.

But similar calls in the past have had little impact on public opinion, and Thursday's ad was greeted with little enthusiasm by ordinary Palestinians.

Hamas' founder, Sheik Ahmed Yassin (search), was killed in an Israeli airstrike Monday, prompting an unprecedented outpouring of outrage on Palestinian streets. Hamas has promised to strike back, saying even Israeli Prime Minister Ariel Sharon (search) is a target.

Israeli troops have engaged Palestinian militants in isolated gunfights since Yassin's killing, but there has been no major escalation in violence. Still, Israelis are jittery, and security has been beefed up throughout the country.

On Wednesday, Israeli soldiers stopped a 16-year-old Palestinian with a suicide bomb vest strapped to his body at a crowded West Bank checkpoint, setting off a tense encounter with soldiers.

Pictures of the boy, Hussam Abdo (search), appeared on the front pages of all major Israeli newspapers Thursday, and the incident dominated radio newscasts.

Several teenagers have carried out suicide bombings, and there has been recent concern that militant groups were turning to younger attackers to try to frustrate Israeli security checks. Earlier this month, Israeli troops stopped an 11-year-old boy allegedly trying to smuggle explosives through the same checkpoint.

In an interview with the Israeli newspaper Yediot Ahronot, Abdo said he wanted to reach the paradise he had learned about in school.

"A river of honey, a river of wine and 72 virgins. Since I have been studying Quran I know about the sweet life that waits there," Yediot quoted the boy as saying.

The family of the teenager said he was gullible and easily manipulated, and the incident was downplayed in Palestinian newspapers. Many Palestinians, including the Palestinian Authority newspaper Al-Hayat Al-Jadida, said they believed the standoff was staged by Israel.

But the incident also revealed simmering anger among many Palestinians about the involvement of children in the conflict.

"Every Palestinian I spoke to today was appalled and disgusted and ashamed and angry," said Iyad Sarraj, a child psychologist in the Gaza Strip.

The intellectuals who signed Thursday's ad — including peace advocate Sari Nusseibeh (search), lawmaker Hanan Ashrawi (search) and Abbas Zaki (search), a leading member of Yasser Arafat's Fatah movement — said revenge attacks over Yassin's assassination would lead to strong Israeli retaliation and further hurt the Palestinian cause.

The group called on the public to "rise again in a peaceful, wise Intefadeh (uprising)."

Some Palestinians said they were skeptical the ad would be greeted with a similar call for restraint by Israelis, noting that Israel has announced plans to kill all militant leaders.

"We had many previous experiences with the Israelis," said Ahmed Radi, 32. "There was a truce with Israel, but Israel has not stopped its aggression."

The Yassin killing was part of Sharon's effort to crush Hamas ahead of a possible Israeli withdrawal from Gaza.

Sharon has suggested the Gaza pullout as part of a plan to separate unilaterally from the Palestinians in the absence of a peace agreement. The plan is expected to include a limited pullback from the West Bank, where Israel would impose a boundary with the Palestinians.

An Israeli delegation — including Sharon's bureau chief Dov Weisglass (search) and National Security Adviser Giora Eiland — is in Washington this week to discuss the plan.

On Wednesday, the Israeli team presented one scenario, showing the Americans a map in which six West Bank settlements would be removed in addition to most Gaza communities, an official said on condition of anonymity. He emphasized that no decision has been made on which option to implement.

Despite several days of relative quiet, both Israelis and Palestinians seemed to be bracing for a new outbreak of bloodshed.

On Wednesday, Hamas leaders pledged to hit back at Israel and target Sharon for death. However, the group said it is not targeting the United States, backing off earlier threats against Americans.

In new violence, several Israeli tanks moved back into the Khan Younis refugee camp in the southern Gaza Strip late Wednesday, where some structures were razed earlier in the day.

An Israeli helicopter fired a missile at a group of militants, residents said, and a policeman was wounded. Palestinians said 15 buildings were wholly or partly demolished. The Israeli forces withdrew early Thursday, an army spokeswoman said.