Israel's Supreme Court ruled Thursday that Prime Minister Ariel Sharon's (search) Gaza withdrawal plan is constitutional, removing the last legal obstacle to this summer's watershed pullout.

Also Thursday, Palestinian leader Mahmoud Abbas (search) was meeting militant groups in Gaza to try to resolve domestic political disputes and keep a shaky truce with Israel alive. Israel and the Palestinians are trying to keep the cease-fire intact to allow them to coordinate the Gaza pullout (search), scheduled to begin in mid-August.

The 11-judge Supreme Court rejected 12 petitions by opponents of the withdrawal from the Gaza Strip and four West Bank settlements, ruling the pullout does not violate the settlers' human rights.

In their 320-page ruling, the judges upheld four technical challenges dealing with financial compensation for settlers to be evicted, but stressed that the withdrawal itself is constitutional. One judge dissented, arguing that a law governing the pullout is unsound and should be repealed.

Yoram Sheftel, an attorney for the settlers, said his expectations were low because the Supreme Court has a tendency of backing the government against Jewish settlers.

Since Sharon already has won parliamentary approval for the withdrawal, the court decision exhausted the settlers' legal options for halting the withdrawal. The plan would uproot 9,000 settlers from their homes.

Justice Minister Tzipi Livni praised the court's decision, and expressed hope the ruling would defuse potentially violent settler resistance to the evacuation.

In recent weeks, opponents of the plan have blocked rush-hour traffic on major highways and sabotaged public buildings. Security officials have warned that a small number of hard-liners will likely resist the pullout by force.

"I hope this ruling makes it absolutely clear to the individual settler that the plan is going ahead," Livni told Army Radio.

The ruling comes as opinion polls show that the public's support for the plan — which was initially around 70 percent — is dropping. Recent polls show support for the plan at around 50 percent.

Despite the judgment, Gaza settler leader Avnr Shimoni said he still hoped that public opinion would l derail the plan.

"The polls show that the public is opposed," he told Army Radio. "In the end this is what will pressure our parliament to decide against this."

Israel and the Palestinians have agreed to coordinate the Gaza pullout to prevent violence or chaos during the operation. But the two sides have made little concrete progress.

Late Wednesday, Israeli Defense Minister Shaul Mofaz and Palestinian Interior Minister Nasser Yousef held talks in what was described as a "positive atmosphere." They agreed to step up cooperation ahead of the withdrawal, officials said.

But Palestinian Cabinet Minister Mohammed Dahlan, a top official in charge of preparing for the withdrawal, said Israeli coordination efforts have been poor. He accused Israel of failing to turn over key information about the settlements and failing to address Palestinian concerns about movement in and out of Gaza after the pullout.

"We are in a race against time. The Israelis are wasting this opportunity," Dahlan told journalists in the West Bank.

A new round of violence has increased Israeli fears that the cease-fire could collapse and militants will fire on settlers and security forces during the evacuation.

Abbas arrived in Gaza on Wednesday night against a background of violence — an Israeli air strike on a mortar launcher and empty vehicle; and rocket fire at Israeli targets by Hamas and Islamic Jihad. On Tuesday, six people were killed in a series of clashes.

Abbas hoped to shore up the truce during his visit. He also was seeking to resolve an election dispute with Hamas. Abbas recently postponed legislative elections, angering the Islamic group.

Israel has said it would like to reopen peace talks after the Gaza pullout, but is demanding that Abbas crack down on militants before returning to the negotiating table.

In Gaza, an explosion rocked a refugee camp Thursday, witnesses said. There were no reports of injuries. The Israeli army said the blast appeared to have been an accident.