Labor chairwoman Shelly Yechimovich sent an official letter of resignation as opposition leader to Knesset Speaker Reuven Rivlin on Thursday.
"Due to the changes in the coalition and Kadima's return to the opposition as its largest party, I am announcing the end to my tenure as opposition leader," Yechimovich wrote.
A Labor spokeswoman explained that the letter was a formal step, meant to facilitate a smooth transition for Kadima leader Shaul Mofaz.
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