Amram Mitzna blamed party rivals for undermining his leadership
Israeli Labour Party leader Amram Mitzna has resigned, three months after leading the party to its worst ever election defeat.
Mr Mitzna, elected to the post only six months ago, said his leadership had been attacked from within the party.
The former dovish general had been coming under increasing pressure over his refusal to join Prime Minister Ariel Sharon's right-leaning coalition.
He told a news conference that constant backstabbing by Labour rivals was the reason for his decision.
"To my great regret, and despite the strong majority with which I was elected (as party head), there were people who did not respect the will of the voters and did everything they could to attack my ability to lead the party," he said.
The former mayor of Haifa was the choice of the peace movement when he was elected to the post in November 2002.
He favoured immediate peace talks - even if it meant sitting down with Palestinian leader Yasser Arafat - and criticised curfews and conditions imposed on the Palestinians by the Israelis.
But the Labour Party barely scraped together half the seats of its long-standing rival, the right-wing Likud, in January's election.
Mr Mitzna angered many in his party over his refusal to join a coalition with Likud, saying Mr Sharon was not committed to the peace process.
More recently he said he would consider joining the coalition if Mr Sharon fully accepted the new peace "roadmap".
Announcing his resignation, Mr Mitzna reaffirmed his belief in Labour's policy of land for peace but said his authority had been undermined by senior party members.
He accused them of placing their own personal political ambitions above the party's interests and blocking his policies.
Israeli political commentators say he is referring to former Defence Minister Binyamin Ben-Eliezer, also a former Labour Party leader, the BBC's David Chazan reports from Jerusalem.
It was Mr Ben-Eliezer's withdrawal from a coalition government headed by Mr Sharon that forced the prime minister to call the last general election.
Mr Ben-Eliezer is now seen as a possible contender for the Labour leadership, our correspondent says.