Lebanon's pro-Syrian prime minister has said he is stepping down after failing to form a new government.
Political turmoil has grown since Hariri's murder
"Today, and after many attempts once again we reached a dead end," Omar Karami said at a news conference
The resignation after weeks of deadlock deepens a political crisis triggered by the assassination of former Prime Minister Rafik Hariri on 14 February.
It means a general election may not have time to take place before the May deadline, as cabinet needs to call it.
"I wrote my apology and deposited it with the president of the republic on Monday evening, but of course we did not announce that upon the request of the president," he said.
"We wanted to allow time for more contacts ... until the last moment for solutions that could help the formation of the government," Mr Karami added.
He indicated that prolonged talks with President Emile Lahoud and parliament speaker Nabih Berri had failed to agree on a list of ministers.
The anti-Syrian opposition has accused Mr Karami and other loyalists of manoeuvring to delay elections, hoping that the popular outrage at Hariri's death may subside.
However, Mr Karami insisted that there was still time to hold the poll before 31 May when the mandate of the current parliament runs out.
Many Lebanese suspect the government and its Syrian backers were somehow involved in the bombing - although this has been strenuously denied by officials.