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Palestinians gave a jubilant welcome to 500 prisoners freed Monday by Israel (search) as part of a truce, but many complained that uprising leaders were not among those released. Hamas militants appeared unmasked in a West Bank (search) city, their leader shouting that there can be no peace "as long as there is a single prisoner in Israeli jails."

Suhail Abu Madala, 35, spent four years in prison and had three more years to serve when he was set free Monday.

"I cannot believe that I'm smelling the air of freedom, that I will see my family," he said, choking back tears after being reunited with brothers and sisters and his 12-year-old son, Mohammed, in the West Bank city of Nablus (search). "Nothing can describe my joy and my feelings."

On the first day of a fence-mending trip to Europe, President Bush pledged to support efforts to resolve the conflict, saying peace based on a two-state solution was within reach.

"Our greatest opportunity, and our immediate goal, is peace in the Middle East," Bush said in Brussels, Belgium.

The decision to release the prisoners led to criticism by some Israelis that the move could re-ignite the bloodshed that has beset the region for more than four years.

"It's true that many of them don't have blood on their hands, but it's not because they didn't try — it's because they didn't succeed," Menachem Landau, a former commander in Israel's Shin Bet security service, told Army Radio.

Relatives of terror victims appealed unsuccessfully to Israel's Supreme Court to block the release, listing Israelis who have been killed over the years by freed Palestinian prisoners. The prisoners released Monday were not directly involved in violence, officials said.

But earlier, Israeli officials indicated it would consider freeing Palestinians convicted of direct involvement in violence, a change in its blanket refusal to release Palestinians with "blood on their hands."

Palestinians also faced internal political turmoil. Leaders suspended a session of parliament when it became clear that a new Cabinet, presented by Prime Minister Ahmed Qureia, would not win a vote of confidence.

Palestinian leader Mahmoud Abbas has been struggling with Qureia over power issues including the makeup of the Cabinet, and the crisis may be a way for him to force the prime minister to resign.

Abbas has made the prisoners a key political and emotional issue and measure of his effectiveness. His brief term as prime minister in 2003 collapsed largely over his pique at Israel's refusal to free veteran prisoners and uprising leaders.

A senior Israeli official, speaking on condition of anonymity, said the release was a goodwill gesture to strengthen Abbas. Almost every Palestinian has had a family member imprisoned by Israel at some point.

All over the West Bank and Gaza, the tearful scenes of joy played out. But again, many Palestinians not directly involved in the release were disgruntled.

Although 400 more are to be released in the coming days, about 7,000 Palestinians would still be behind Israeli bars, including leaders of the uprising. Palestinians complained that most of the freed prisoners were small-time offenders or near the end of their terms.

"There will be no peace as long as there is a single prisoner in Israeli jails," Hassan Yousef, West Bank leader of the Islamic militant group Hamas, shouted through a bullhorn.

In Nablus, a crowd of 15,000 welcomed 100 prisoners. Dozens of gunmen fired in the air, among them Hamas members appearing with their weapons in public and unmasked for the first time since Israeli and Palestinian leaders agreed to an unofficial truce this month.

Near the West Bank town of Jenin, a 30-year-old bystander was killed by celebratory fire and four people were wounded. A long convoy of cars, led by gunmen flying a green Hamas flag from their vehicle, escorted the released prisoners into town.

Landau, the former Shin Bet commander, said about one in seven Palestinians freed in previous rounds returned to hostile activity, and that releasing prisoners at this stage is unusual.

"First you leave the territory, and then you free prisoners," he said. "I fail to see the logic of this."