Lebanon's parliament has adjourned a crucial session to elect a new president until 23 October.
Saad Hariri leads the majority March 14 coalition in parliament
Speaker Nabih Berri said there were not enough MPs to make the two-thirds quorum, after members of the opposition pro-Syrian bloc stayed away.
The opposition wants to prevent the Western-backed majority from electing an anti-Syrian head of state.
Pro-Syrian Emile Lahoud is due to step down in two months, bringing three years of political crisis to a head.
Parliament has until late November to choose a successor who, by political consensus, must be a Maronite Christian.
Lebanon has been locked in political crisis since the assassination of former Prime Minister Rafik Hariri in February 2005.
The anti-Syrian 14 March Movement under Prime Minister Fouad Siniora has a dwindling majority of 68 in the 128-seat Chamber of Deputies after the murders of five of its members.
Nassib Lahoud: Government candidate. Former US ambassador. Leading industrialist
Michel Aoun: Opposition candidate. Former army commander who fought Syria during civil war. Returned from exile in 2005. Vocal opponent of government
Michel Suleiman: Army commander since 1998. Electing him requires constitutional amendment
Riad Salameh: Central bank governor since 1993. Widely respected at home and abroad. Election requires constitutional amendment
Boutrous Harb: Pro-government candidate. MP and former minister
Jean Obeid: Possible consensus candidate. Foreign minister 2003-2004
This is not enough for the two-thirds majority required in the first round of voting.
Antoine Ghanim was the latest anti-Syrian MP to be killed when he was caught in a car bombing last week.
Tanks and troops ringed the parliament building for Tuesday's planned session and anti-Syrian MPs were escorted to there under tight security from the seaside hotel where many have been staying.
Some opposition MPs mingled in the corridors with their opponents but remained outside when the bell rang for them to take their places in the chamber.
"Despite everything, we continue to seek constructive dialogue and practical discussion with the various opposition blocs to salvage the presidential election," said deputy house speaker Farid Makari, reading a statement from 14 March.
The pro-Syrian coalition is led by the Shia Islamist movement, Hezbollah, with support from the Maronite Christian leader Michel Aoun.
The delay in voting for a new president gives more time, in theory, for intensive consultations to break the deadlock and produce agreement on a compromise candidate, says the BBC's Jim Muir in Beirut.