At least four people have been killed and dozens wounded in a blast in an area near the presidential palace on the outskirts of Beirut, according to media reports.
A senior army officer was among those killed in Wednesday's blast, security sources said.
They said the slain officer, chief of operations Brigadier-General Francois al-Hajj, was a leading candidate to take over as army commander if and when current commander General Michel Suleiman was elected president.
The roadside-bomb blast took place in Baabda, a Christian suburb east of Lebanon's capital.
Vote postponed
The attack came after parliament postponed for the eighth time a vote to elect Suleiman as a compromise president.
Nabih Berri, the parliamentary speaker, said in a statement the session would be postponed until December 17 "to allow for more consultations to agree on the election".
Suleiman needs parliamentary approval and a constitutional amendment before he can assume the post.
Suleiman, who is on good terms with Hezbollah, the Shia opposition group, was appointed to his post in 1998 when Syria had military control of Lebanon.
Nevertheless, he has gained respect across the political spectrum for keeping the army neutral and curbing outbreaks of civil strife.
The postponement came after the majority coalition of 68 legislators said they would boycott Tuesday's session.
The country's opposition leader, Michel Aoun, has also withheld support until they are promised "rights" in decision-making, saying he doubts that a new president will be elected before the year ends.
Opposition blamed
Saad Hariri, the majority leader, accused the opposition of seeking to scuttle the presidential election, saying those who stood in the way "will shoulder the responsibility".
Lebanon moved into a leadership vacuum after Emile Lahoud, the pro-Syrian president, stepped down on November 23.
The presidency is reserved for a Maronite Christian under Lebanon's sectarian power-sharing system.
The 128-seat legislature needs to obtain a two-thirds quorum to begin voting for the president, as well as to amend the constitution to allow an army chief to hold the post.
Source: mongenie