Lebanese leaders were approaching agreement on Tuesday on a deal to elect the army chief as president, with France's foreign minister holding talks in Beirut to help seal it.
Rival Lebanese leaders have all come out in support of General Michel Suleiman to take the presidency, vacant since November 23, when the term of pro-Syrian Emile Lahoud ended.
While consensus on one name has finally emerged, the anti-Syrian governing coalition and the Hezbollah-led opposition, backed by Syria, have yet to work out all the details.
Parliament has been convened for Friday, but the vote will only go ahead then if the deal is sealed. Political sources say the vote might still have to be delayed for a few more days.
French Foreign Minister Bernard Kouchner arrived in Beirut in a previously unannounced trip and began separate talks with rival leaders. His spokeswoman said he would stay in Lebanon as long as is useful to help in the talks over a new president.
After agreement on General Michel Suleiman, Kouchner is due in Beirut to complete the mission, a senior political source had said shortly before the French minister arrived.
Kouchner led previous European mediation efforts to forge an agreement between the majority, backed by the United States, and the opposition, backed by Syria and Iran.
One of the main tasks for Kouchner this time was to remove conditions placed by Christian opposition leader Michel Aoun to Suleiman's election, political sources said.
A deal would defuse a power struggle that has paralyzed Lebanon for more than a year and triggered the worst internal strife since the 1975-1990 civil war.
Neither side has enough lawmakers to secure a two-thirds quorum, leaving Lebanon without a president.
Suleiman, 59, assumed his post in 1998 when Syria still controlled Lebanon. He has good ties with Hezbollah.
The governing coalition has worked to try to curb Syria's influence since it was forced to withdraw troops from Lebanon in 2005. It had hoped to replace Lahoud, a close Damascus ally, with one of its own.
But the governing coalition now see Suleiman as their only option, preferring him to a presidential vacuum that could destabilize Lebanon. Both sides have retreated from threats of unilateral action that could have triggered violence.
The source said a deal on Suleiman would include agreement on the shape of the new government and the outline of an election law for a parliamentary election in 2009.
The current crisis erupted in November 2006 when opposition ministers quit the government of Prime Minister Fouad Siniora over demands for veto power. The crisis spiraled and at times lead to deadly sectarian clashes earlier this year.