Lebanon's embattled caretaker prime minister has postponed an expected announcement that he is stepping down after failing to form a unity cabinet.
Karami has presided over a government in limbo since February
Omar Karami said he needed to consult further with his pro-Syrian allies, reversing a pledge made a day earlier.
The move comes after Syria confirmed for the first time that it would pull all its troops out of Lebanon before parliamentary elections due in May.
More Syrian troops were observed leaving Lebanon on Tuesday night.
Two dozen Syrian military trucks drove east over the border and intelligence officers were seen burning papers at several Syrian-occupied buildings in the Bekaa valley.
Mr Karami made the surprise announcement that he would resign after a meeting with President Emile Lahoud - who stands at the centre of the row about Syria's influence over Lebanon.
"I have informed Mr Lahoud that I am preparing to announce my decision to stand down because of the impossibility of forming a government of national unity," he said.
"But I will do so only within the next 48 hours so as to consult with my allies" he told reporters.
He denied any rift with Mr Lahoud over the latter's reported wavering on a commitment to form a broad-based government.
"We are in the same camp," Mr Karami stressed.
Syrian Foreign Minister Farouq al-Shara made the pledge to pull Syrian forces out completely before May elections in a letter to the United Nations.
BBC correspondent Kim Ghattas says it is the clearest indication of Syria's commitment to withdraw its troops from Lebanon.
More Syrian troops and equipment crossed the border overnight
But there are doubts whether the vote will take place before 31 May as scheduled because of the political crisis, she adds.
Syria has already been withdrawing troops, spurred on by the outcry following the assassination of former Lebanese Prime Minister Rafik Hariri on 14 February.
Lebanese opposition groups accuse Syria of being behind the killing. Two weeks of street protests led to the downfall of Mr Karami's pro-Syrian administration.
Mr Karami was reinstated as prime minister on 10 March - after a massive loyalist rally in Beirut - but it became clear long before Tuesday that he would be unable to form a national unity government.
Syrian troop levels, which once stood at 40,000, are down to about 8,000 after departures in the last few days.
A UN resolution sponsored by the US and France in September called for a full withdrawal of Syrian troops and intelligence services.
The Security Council has been meeting to discuss whether to authorise an international investigation into Mr Hariri's death.
This was recommended by a UN fact-finding mission which said a Lebanese inquiry into the killing suffered from "serious flaws".
Syrian military intelligence "bore primary responsibility for a lack of security, protection and law and order" at the time of Hariri's death, the mission also said.
Mr Shara rejected the mission's findings, saying they ignored "cordial and long relations" between Hariri and Damascus. Syria denies any involvement in the killing.
Hariri resigned as prime minister on 8 September over a constitutional amendment that gave President Lahoud three more years in office - a move widely believed to have been forced through by Syria.