JERUSALEM – Prime Minister Ehud Olmert said yesterday that countries that don’t have diplomatic relations with the Jewish state should not participate in the international peacekeeping force that will police a truce along the Lebanese border, his office said.

The decision complicated efforts by the United Nations to form a 15,000-strong peacekeeping force, which along with an equally large Lebanese army contingent will help enforce the truce that ended 34 days of fighting between Israel and the Lebanese guerrilla group Hezbollah.

The announcement, which came shortly before the arrival of U.N. envoy Terje Roed-Larsen in Israel, was made during the weekly meeting of Olmert’s Cabinet, his office said.

“The prime minister said that countries without diplomatic relations with Israel should not comprise the international force,” said David Baker, an official in Olmert’s office said.

During a phone conversation with Italian Prime Minister Romano Prodi, Olmert suggested that Italy lead the international force, according to Olmert’s office as Rome signaled its willingness to do so.

Prodi said that Italy intends to send a “significant” force and that he would take up the matter with his parliament as soon as possible, the statement said.

The U.N. cease-fire resolution does not explicitly give Israel authority to block countries from joining the peacekeeping mission, but it does say the force should “coordinate its activities … with the government of Lebanon and government of Israel.”

“Israel believes that it’s best that we have the ability to be able to communicate with the international forces,” said Foreign Ministry spokesman Mark Regev. “As a practical matter, we would have a problem if the international forces don’t have the ability to talk to us.”

He said the composition of the force should be coordinated between Israel and Lebanon, just as the cease-fire resolution was.

Regev also urged the wider international community to follow through on its commitment to provide troops, saying the cease-fire could be in danger if the peacekeepers don’t quickly deploy.

Indonesia, Malaysia and Bangladesh – Muslim countries that do not have diplomatic ties with Israel – are among the only countries to offer front-line troops for the expanded force.

Europe, which was expected to lead the force, has been slow to make any firm troop commitments. U.N. officials have called on the Europeans to offer more troops to balance pledges from Muslim countries.

Italy would be willing to lead the military peace mission in Lebanon should the United Nations ask it to, Piero Fassino, who leads the largest party in Prodi’s center-left coalition, said in an interview published yesterday.

“In case U.N. headquarters put forward the request to our country to lead the mission, our country will not refuse, even though it is not seeking it,” Fassino was quoted as telling Rome daily Il Messaggero.

Italian Foreign Minister Massimo D’Alema also spoke by phone on Sunday with U.S. Secretary of State Condoleezza Rice, who “expressed the strong appreciation and full backing of Washington for the action that Italy is carrying out aimed at implementing the resolution,” the foreign ministry said in a statement.

Rice also encouraged Italy to seek a “strong role” in the peace force, the ministry said.

The U.N. wants 3,500 troops on the ground by Aug. 28.

France, which commands an existing, 2,000-strong force in Lebanon known as UNIFIL, had been expected to make a significant new contribution that would form the backbone of the expanded force. But French President Jacques Chirac disappointed the United Nations by announcing Thursday that France would add just 200 combat engineers to its current 200-member contingent in Lebanon.