By Daniel Williams,  Dec. 4 (Bloomberg) -- The shooting death of a Shiite Muslim youth in Beirut increases the risk of converting Lebanon's political power struggle into a sectarian conflict. Portraits of Ali Ahmed Mahmoud, 20, who died during a Shiite-Sunni Muslim street fight yesterday, hung at downtown plazas occupied by Hezbollah, the Shiite party that is campaigning to topple Lebanon's pro-Western government. Placards declared Mahmoud a martyr.

Army units appeared at intersections that separate Shiite and Sunni areas. A row of a dozen armored personnel vehicles topped with recoilless rifles lined a boulevard between KasKas, the scene of the killing, and the Shiite neighborhood of Dahiyeh. ``We don't know what is going to happen next,'' said Hamed Jabasini, 40, a chocolate merchant. ``This is something the leaders bring to us by their politics.''

The opposition protests, aimed at toppling Prime Minister Fouad Siniora, began Dec. 1 One of the main opposition is. Hezbollah's militia triggered war with Israel in July when it abducted two Israeli soldiers. The party wants to get more say in government and divert Lebanon from close ties with the U.S. Iran and Syria back Hezbollah in this quest. The Bush administration supports Siniora and regards Hezbollah as a terrorist tool of the governments in Tehran and Damascus.