Israel's former foreign minister and opposition leader, Tzipi Livni, has announced that she is resigning from the country's parliament, the Knesset.
However, Ms Livni said she was not withdrawing from public life and would remain a member of the Kadima party.
Her decision comes just over a month after she lost Kadima's leadership.
Ms Livni's successor as Kadima leader, Shaul Mofaz, had said he wanted her to help the party return to power in early elections widely expected this year.
Kadima is currently the biggest party in the Knesset, but recent polls have suggested the number of seats it holds could be halved.
Israel 'at threat'
Ms Livni submitted her resignation to Knesset Speaker Reuven Rivlin on Tuesday.
Speaking to reporters before the meeting, she said she was "leaving the Knesset at this point, but I'm not retiring from public life", adding that Israel was "too dear" to her.
"I was by Ariel Sharon's side on the day it was decided to form Kadima. It was founded in aim to create a government of hope and responsibility."
Ms Livni said she did not regret decisions which might have led to her losing the leadership, saying she was not "sorry for not backing down in the face of political blackmail - even when the price was being in the government - and for not willing to sell the country to the ultra-Orthodox".
"And I'm definitely not sorry for the main issue I promoted. Even if the Israeli-Palestinian conflict isn't in vogue right now, there's an urgent need to reach a permanent agreement with the Palestinians as well as with the Arab world," she added.
The former foreign minister also warned that Israel's existence was under threat because of its current leadership.
"Israel lives on the mouth of a volcano, the international clock is ticking, and the existence of a Jewish, democratic state is at threat," she said.
"The real danger is a politics that buries its head in the sand," she said, adding that it did not "take a Shin Bet chief to know that".
That was an apparent reference to criticism of Prime Minister Benjamin Netanyahu's policies on Iran and the Middle East peace process by Yuval Diskin, former head of Israel's internal security agency.