Tensions are escalating between Foreign Minister Avigdor Lieberman and Prime Minister Benjamin Netanyahu, and despite attempts by both sides to cool tempers, a confrontation between the two figures appears virtually inevitable.

Votes by Yisrael Beiteinu ministers against the state budget this weekend, the battle over the conversion bill, the foreign minister's appointment Friday of an acting UN ambassador without Netanyahu's consent and Lieberman's call for a "disengagement" from Gaza on the eve of the premier's Egypt visit - all have only exacerbated an already strained working relationship.

Open gallery view Foreign Minister Avigdor Lieberman and Prime Minister Benjamin Netanyahu in the Knesset in 2009. Credit: Archive / Tess Scheflan

Sources close to Netanyahu said the deterioration has been perceptible for weeks, peaking when Lieberman fumed at being left out of arranging the June meeting in Brussels between Industry, Trade and Labor Minister Benjamin Ben-Eliezer and the Turkish foreign minister.

Still, the sources said, Lieberman's actions over the past few days came as a surprise to the prime minister. Netanyahu learned of the foreign minister's unilateral appointment of an acting UN envoy by reading it in the press, and reportedly denounced the move as unacceptable. The prime minister had delayed filling the post for months, hoping to appoint a senior public figure rather than the relatively unknown diplomat Lieberman chose, Meiron Reuven.

Lieberman's "disengagement" plan, widely viewed as a slight to Cairo ahead of Netanyahu's visit, was neither coordinated with the prime minister nor received his approval - points Netanyahu is expected to emphasize at today's meeting with Egyptian President Hosni Mubarak.

"Policies on this matter are set by the prime minister and the cabinet," a Netanyahu source quoted the prime minister as saying this weekend. "That's how it has always been, and that's how it will remain."

In closed-door meetings over the weekend, Netanyahu said that in the coming days he intends to ask Lieberman to explain his actions. The prime minister and foreign minister had already held conciliatory meetings after the Ben-Eliezer incident, though this time Netanyahu is expected to strike a firmer tone in a bid to iron out the differences of opinion between the two officials and their respective parties.

Budget stunner

Netanyahu was reportedly stunned during Friday's budget meeting by the behavior of Yisrael Beiteinu ministers, who had apparently received instructions from Lieberman before his trip to Kazakhstan to firmly oppose the budget backed by Netanyahu and Finance Minister Yuval Steinitz.

Leading the Yisrael Beiteinu offensive was Tourism Minister Stas Misezhnikov, appointed by Lieberman to oversee budget negotiations in his stead. A source at the cabinet meeting said Misezhnikov addressed Netanyahu bluntly, essentially "hurling insults" at the prime minister.

"All of the other Yisrael Beiteinu ministers joined him shortly after," the source said. "It was like a well-synchronized orchestra."

Another item on the Netanyahu-Lieberman agenda is the row over a bill that would ease the terms of religious conversion, scheduled to be heard in the Knesset a week from now, before the summer recess gets underway. Under pressure from U.S. Jewish groups, Netanyahu has sought to stall the bill's passing, but Lieberman and members of his Knesset faction maintain that failure to pass it would signify a violation of coalition agreements.

Amid the rising tension, Lieberman and his associates have issued conciliatory statements insisting they have no intention of quitting the coalition. They explained the UN ambassador's appointment as the result of an urgent need to fill a vacant post, and noted that the foreign minister had raised his plan to sever ties with Gaza on several earlier occasions.

"We believe the matter will ultimately be settled," Lieberman associates said.

This weekend Misezhnikov reiterated that his party is not planning to leave the coalition. "We don't want to replace the coalition or leave the government that we built with our own two hands," he said. "But we aren't the ones who sent Fuad [Ben-Eliezer] to talk to the Turks. When Netanyahu needed us a week ago in the Ministerial Committee for Legislation, he knew exactly how to speak to us nicely and make all kinds of promises over the budget."

On the budget, Misezhnikov said, "This is not how you conduct negotiations. Whoever thinks he has defeated us is plain wrong."