FACTBOX-Timeline for Israeli coalition talks

(Reuters) - Israeli Foreign Minister Tzipi Livni is trying to form a new government and hit a major snag on Friday when a key Jewish religious party refused to join her coalition, raising the prospect of an early parliamentary election.

These are key developments and dates to watch:

* On September 17, Livni was elected leader of the centrist Kadima party, succeeding Prime Minister Ehud Olmert, who stepped down after being investigated for corruption and fraud

* On September 22, Olmert resigned as premier and President Shimon Peres asked Livni to form a new government. Meanwhile, Olmert continues to run the country in a caretaker capacity

* A day later, right-wing opposition Likud leader Benjamin Netanyahu, a former prime minister, rejected an offer from Livni to join a coalition cabinet. Likud is ahead in polls and hopes to take power if Livni fails to form a government

* After talks slowed by Jewish holidays, on October 13, Kadima signed a draft coalition pact with the left-wing Labour party of Defence Minister Ehud Barak, also a former premier. Together, the two parties have 48 of the 120 seats in the Knesset.

* On October 20, as expected Peres gave Livni a further two weeks to try to form a government. If she fails, Peres could ask another parliamentarian to try. More likely there would be a parliamentary election, well ahead of a scheduled vote in 2010.

* On October 23, Livni set a deadline of October 26. She said if there was no deal by Sunday she would throw in the towel. She has set a meeting with Peres for 5 p.m. (1500 GMT) on Sunday.

* On October 24, the ultra-Orthodox Shas party, which has 12 seats in parliament and has long been a fixture in Israel's shifting coalitions, said it would not join a Livni government, citing her willingness to negotiate with Palestinians on giving them a part of Jerusalem as capital of a possible new state.