Brigadier General Francois al-Hajj was killed in a car bomb on Wednesday, the ninth figure to be assassinated in Lebanon in less than three years. He was the first military officer to be killed.
Hajj, who had good ties to Syria's allies in Lebanon including Hezbollah, had been tipped to take over as army chief from General Michel Suleiman, who could be elected president by parliament as early as next week.
"In the name of your precious blood, we urge everyone to take a brave historic decision that would lead us to building confidence and communication between the sides and achieve reconciliation and consensus without any preconditions," Major General Shawki al-Masri, the army's chief of staff, told the funeral service for Hajj at a church north of Beirut.
Masri said "blood messages," such as Hajj's killing, were meant to weaken the foundations of Lebanon, as well as the army.
Schools, banks and public offices across the country were closed for a day of mourning. The killing heightened tensions in Lebanon, in the throes of its worst political crisis since the 1975-1990 civil war.
After weeks of wrangling, pro- and anti-Syrian camps have agreed to nominate Suleiman for the presidency, which has been vacant since Emile Lahoud's term ended on November 23.
Little progress has been made, prompting many politicians to call for a quick deal to allow Suleiman's election.
Rival leaders rubbed shoulders at the church in Harisa where the funeral service took place. Hundreds of mourners packed the church, led by the wife and three children of the slain officer.
Suleiman and his generals received condolences after the service. Hajj's coffin, draped in a Lebanese flag, began a two-hour drive to his southern hometown of Rmeish for burial.
Güncelleme Tarihi: 14 Aralık 2007, 14:18
Lebanon asked the United Nations to help it investigate Hajj's killing. A U.N. commission is already investigating the 2005 assassination of former Prime Minister Rafik al-Hariri and other political attacks.
It is due to hand over its findings to a special tribunal being established in the Netherlands.