Defense Minister Ehud Barak and his four allies quit the Labor Party in a process facilitated by the intensive and secret intervention of Prime Minister Benjamin Netanyahu and his associates.

"The procedure was carried out like an elite General Staff [military] operation," an aide to the premier said Monday following Barak's announcement at the Knesset.

The process of Labor's split began two weeks ago, after a wave of attacks on the part of party ministers against Barak after senior U.S. officials told Haaretz that the Obama administration was furious with the defense minister for "deceiving" them about his political clout with regard to the peace process.

Secretary of State Hillary Clinton and Obama's senior advisers say that for more than a year and a half Barak misled them about his persuasive powers with Netanyahu regarding his ability to bring him toward an agreement with the Palestinians.

A number of ministers from Netanyahu's Likud party and the right-wing Yisrael Beitenu have said that since the report emerged regarding the U.S. anger, the defense minister appeared at cabinet and Knesset meetings looking as though "his world had fallen apart".

A source who met with Barak on a recent weekend described his emotional state as "quite bad".

Associates to the premier said that Netanyahu's bureau chief, Natan Eshel, had been responsible for contacts with Barak and fellow Labor MK Shalom Simhon regarding the breakaway.

Netanyahu supported the process and said he was "sick of getting ministers on condition for the cabinet and of waiting for the Labor Party committee's decisions."

The prime minister believes that the government will remain stable despite Barak's split and the expectation that the remaining Labor ministers will quit the coalition.

Deputy Defense Minister Matan Vilnai, who joined Barak in quitting Labor, will likely be assigned a ministerial office once one opens and MK Orit Noked may also be "upgraded" to minister.