FACTBOX: The main players in Lebanon's crisis

(Reuters) - Rival Lebanese leaders are scheduled to hold talks in Qatar on Friday aimed at resolving 18 months of political conflict that has triggered bouts of lethal fighting, paralyzed government and left the country without a president since November.

Following is some background on the main political leaders and parties involved the crisis in Lebanon:

RULING COALITION

- The March 14 coalition holds a majority of 68 seats in the 128-member parliament and backs the government of Prime Minister Fouad Siniora. The coalition is staunchly opposed to any Syrian influence in Lebanon and is backed firmly by the United States, France and regional power Saudi Arabia. Its key players are:

* Saad al-Hariri: The coalition leader is the Sunni Muslim son and political heir of assassinated former Prime Minister Rafik al-Hariri. He also holds Saudi citizenship.

* Walid Jumblatt: The leader of the Druze community and the Progressive Socialist Party (PSP). His party played a prominent role in the 1975-1990 civil war but he shifted his alliance with Syria in 2004 and has become a U.S. ally.

* Samir Geagea: The Maronite Christian leader of the Lebanese Forces, a civil war militia turned political party. He was released from 11 years of jail after Syrian forces left Lebanon in 2005 following a pardon over civil war murders.

OPPOSITION

-- The opposition, which holds 59 seats in parliament, is led by Hezbollah and demands full participation in the running of the country. Another parliamentary seat remains vacant since the September assassination of a member of the ruling coalition.

The opposition's key components are:

* Hezbollah: The Shi'ite Muslim party is the largest group in the opposition and the only Lebanese faction officially allowed to keep its arms after the 1975-90 civil war. It is supported by neighboring Syria and Shi'ite Iran. Hezbollah showed its military prowess in a 34-day war against Israel in 2006. Its adversaries favor Hezbollah's eventual disarmament or integration into the army, citing U.N. Security Council resolutions 1559 and 1701. But the group insists on keeping its weapons to defend Lebanon against what it sees as Israeli threats.

* Amal: A Syrian-backed Shi'ite group which along with Hezbollah represents the vast majority of Lebanon's Shi'ites, the largest community among the country's 4 million population. Its leader Nabih Berri is parliament speaker.

* Michel Aoun: A Maronite former army commander, Aoun returned to Lebanon in 2005 days after Syrian troops withdrew. He had spent nearly 14 years in exile. Lebanon's civil war officially ended when Syrian-led forces stormed Christian east Beirut in 1990, crushing Aoun's forces and driving him to exile in France. Aoun now leads the Free Patriotic Movement and holds the largest Christian bloc in parliament.