The Israeli and Palestinian prime ministers planned to meet this week in the highest-level encounter in three years, but the two sides disagree sharply about a new, U.S.-backed Mideast peace plan.

International efforts to promote the "road map" to end 31 months of violence and set up a Palestinian state remained intense, despite Secretary of State Colin Powell's (search) failure during his recent visit to extract an Israeli pledge to accept the plan.

Greek Foreign Minister George Papandreou, whose country holds the European Union presidency, arrived to keep the pressure on. Powell left on Monday.

The meeting between Israeli Prime Minister Ariel Sharon (search) and his Palestinian counterpart, Mahmoud Abbas (search), will take place Friday, said Israeli Foreign Minister Silvan Shalom. Palestinian officials, speaking on condition of anonymity, said the meeting would take place before the end of the week.

The last meeting between Israeli and Palestinian leaders was in 2000, when then-Israeli Prime Minister Ehud Barak and Palestinian leader Yasser Arafat were engaged in peace talks that eventually broke down, and violence erupted.

Sharon has refused to see Arafat, and the United States has accepted Sharon's boycott of the veteran Palestinian leader, charging that Arafat is involved in Palestinian terrorism.

However, European nations reject that approach. Papandreou, who arrived Monday for talks, is to meet Arafat late Tuesday after seeing Sharon.

Papandreou has said his message to all, including Arafat, is the same: support for the road map. "This is an opportunity we must not allow again to fail," he said.

He said he would tell Arafat and Abbas, "It is absolutely necessary to move forward, especially on the issue of security."

Israel is demanding concrete Palestinian steps against militants responsible for attacks against Israelis as a condition for movement on the plan.

Palestinians have accepted the road map, a three-stage blueprint which begins with an end to violence, Israeli army pullbacks and a halt in settlement building in the West Bank and Gaza Strip. The plan then allows for a Palestinian state with provisional borders — perhaps by the end of the year — and hopes to resolve tough issues like borders, Palestinian refugees and Jerusalem in the last stage.

Israel has presented 15 objections to the plan. The main one is that Israel wants its concessions to follow a Palestinian dismantling of terror groups, while the Palestinians say steps must proceed in parallel, as the road map suggests.

Powell flew to Cairo on Monday, for talks with Egyptian leaders, leaving Palestinians disappointed. "Mr. Powell came without a positive Israeli response (to the road map) ... and that is very unfortunate," said Palestinian Cabinet Minister Saeb Erekat.

Sharon is to discuss the Israeli points with Bush next week in Washington. Powell said on Sunday that those talks will include the question of Israeli settlements, but Israeli officials insisted they do not expect a confrontation.

"There is no pressure from the United States," Sharon said Monday. "We have a special relationship based on trust."

Also Monday, the Israeli military banned foreigners entering or leaving the Gaza Strip, citing security needs. The ban, the harshest in years, included reporters and aid workers.

The local Foreign Press Association demanded access for journalists be restored and charged that the closure was "extremely disturbing and suggests an utter disregard for basic press freedoms."

Later Monday, the army spokeswoman issued a statement easing the closure, saying journalists wishing to enter Gaza must register with the army in advance and affirming the army is "aware of the importance of unimpeded access" to Gaza, which is home to more than a million Palestinians and about 6,000 Jewish settlers.

Three days earlier, the army had announced that foreigners entering Gaza would have to sign a form undertaking not to enter "combat zones" and appearing to release the army from responsibility for their safety.

On Tuesday, police arrested 13 leaders of the Islamic Movement in Israel on suspicion they funneled money to illegal groups.

The arrests were expected to heighten tensions between Israel's large Arab minority and authorities. Relations were already strained by the killing of 13 Arab protesters by police in anti-government protests in October 2000.

Among those arrested was the leader of the group, Sheik Raed Salah. The arrests capped a two-year undercover investigation by the police fraud squad and the Shin Bet security service.

Police said the detainees were suspected of laundering money from abroad for organizations that are outlawed in Israel, and of providing other services. Police did name the illegal organizations, but Israeli media reports said Salah and his supporters were suspected of aiding the militant Islamic Hamas.