Lebanon's rival leaders sat down together in an unprecedented political dialogue Thursday aimed at resolving the country's deep divisions since the end of Syrian domination, amid warnings that failure could worsen the slide toward instability. Hours before the gathering in Beirut, a small bomb exploded in a courthouse before dawn in the Christian port of Jounieh outside of Beirut. It was the latest in a chain of bombings in Lebanon that began in early 2005. Blasts have killed 32 people, including former prime minister Rafik Hariri in a February 14, 2005, attack. Other explosions have been in mainly Christian districts, often causing damage and fear but no casualties. The attacks have heightened concerns over the sharp splits in Lebanon in the wake of Syria's withdrawal from the country last year. Thursday's gathering was the first of its kind since the end of Syria's nearly 30-year control of the country. Rival political leaders - Muslim and Christian, pro- and anti-Syrian - sat down together in the downtown Beirut parliament building in hopes of resolving their differences. But it will be an uphill struggle to reach an agreement, since they are tackling some of the issues at the heart of the divisions, including demands for the ousting of pro-Syrian President Emile Lahoud and the disarming of Hizbullah. The anti-Syrian bloc accuses Damascus of complicity in the Hariri slaying and want to push ahead a UN investigation into the assassination, which has already implicated Syrian officials. Syria's allies say the investigation is political and aimed at railroading Damascus and undermining Syrian President Bashar Assad. "Failure is forbidden because its consequences are grave," warned Parliament Speaker Nabih Berri, who called the meeting in the legislature. Among the politicians who showed up for the talks were Saad Hariri, a Sunni Muslim who controls the largest parliamentary bloc; Walid Jumblatt, the Druse political leader; Shi'ite Muslim Hizbullah leader Sheik Hassan Nasrallah; Michel Aoun, a Christian who leads the parliamentary opposition; and Christian leader Samir Geagea. Nasrallah and Geagea met for the first time. The only major politician not invited was Lahoud. Lahoud has resisted calls by the anti-Syrian bloc to step down - calls led by Hariri, the son of the slain former prime minister, and Jumblatt. The meeting's opening was delayed by about an hour because of differences over representation - and even seating - at the table.