The International Court of Justice, the highest judicial arm of the United Nations, was to deliver its ruling on the barrier later Friday. The Israeli newspaper Haaretz, however, said it had obtained documents indicating a 14-1 ruling that the barrier is illegal and demanding Israel dismantle it and compensate those Palestinians whose property was confiscated.
"The construction of the wall being built by Israel, the occupying Power, in the Occupied Palestinian Territory, including in and around East Jerusalem, and its associated regime, are contrary to international law," the ruling says, according to the paper.
The sole opponent was the American judge, Thomas Buerghenthal.
Israel has already said that it will not abide by the World Court's decision, reports CBS News Correspondent Robert Berger, because it does not acknowledge its authority to rule on the barrier.
"It's not we who should be before the international court, it's they, the Palestinian terror regime," said Finance Minister Benjamin Netanyahu, who called the barrier legitimate self-defense.
"Does it prove effective against suicide bombers? Yes! That's why we're building it," he said.
Demonstrators for and against the barrier, which Palestinians consider a land grab, shouted their concerns ahead of the decision.
A banner where hundreds were gathering in the West Bank town of al-Ram, near Ramallah, read: "The Israeli wall, longer and higher than Berlin, but just as disgusting."
Some demonstrators were already claiming victory. Jamal Juma, coordinator of a Palestinian group called The Anti-apartheid Wall Campaign, welcomed the reports of a 14-1 court decision. "It's a great decision. We are thrilled. It very clearly delegitimizes the wall and demands that it be pulled down," Juma said.
Only 6 miles away, a few dozen Israelis gathered by a concrete section of the fence on the outskirts of Jerusalem, held pictures and banners of terror victims, waved Israeli flags, and displayed a large banner reading: "Fence out terrorism."
The court's opinion is only advisory, and Israel has made clear it will not be bound by it. However, a ruling against Israel would add international pressure to stop construction of the 425-mile complex of towering concrete walls, razor-wire fences, trenches and watch towers. About a fourth has been completed so far, roughly along the pre-1967 border but with many dips into the West Bank.
The Israeli-Arab Hadash party also filed a no-confidence motion Friday against the government over the security fence. Such motions are common, and there wasn't expected to be much support for it.
Israeli officials — who have tried to downplay the court's consideation of the barrier — said little ahead of a formal decision. Privately, they also expect a ruling critical of Israel, but Israel's position is that it will follow its own legal judgments.
"There are limitations imposed on the fence by the Supreme Court in Israel, and we will obey our Supreme Court's decisions and not a panel of European Union judges who are not exactly friendly toward Israel," Justice Minister Yossef Lapid told Israel radio.
Armed, they hope, with a court ruling that the barrier is illegal, the Palestinians want the U.N. General Assembly to demand Israel dismantle it. If Israel refuses, the Palestinians want the Security Council to enforce it, which could draw a U.S. veto.
"We think that Israel and all the other countries should respect the decision of the court," Nasser al-Kidwa, the Palestinian U.N. observer, said Friday from The Hague. "We will not excuse the Security Council from its responsibilities."
Israel's Army radio reported that the Defense Ministry expects Palestinian violence in the wake of any decision handed down. Palestinian Cabinet minister Saeb Erekat dismissed any suggestion Palestinian areas would erupt.
"I think this going to the high court is a way of seeking a diplomatic solution, not a way to violence," Erekat said.
Tayseer Tamimi, a Muslim cleric who addressed the al-Ram rally from beneath a canopy adorned with a picture of Palestinian leader Yasser Arafat and a Palestinian flag, urged people to protest the wall, but did not advocate violence. He also criticized the Arab world for staying silent when Israel began construction.
Also on Friday, the Israeli army spokesman's office said a Palestinian threw a hand grenade toward Israeli soldiers who had asked him to stop for inspection at a main junction near the Gaza town of Beit Hanoun. During an exchange of gunfire, the Palestinian escaped unharmed, the military said. No Israeli soldiers were injured.