According to Lebanese television, a group of Shia protesters were walking home from the protest to their neighborhood near the Shatilla refugee camp. Apparently, they were attacked by a group of March 14 supporters, but it is unsure if the attackers were Sunni or Christian.
The details are still coming out, but it seems a Shia youth of twenty years was shot and killed by the attackers. Another in the group may have been stabbed as well.
This is really disconcerting, not only for the obvious reason that someone was murdered in the street, but for the fact that up until now, clashes between opposition supporters and government supporters had stayed at a minimum. I can imagine that this sort of an act will not go without a reprisal from Shia groups.
Opposition supporters interviewed on television stated that the March 14 group had their protest last week without any attacks by opposition supporters and were dismayed that they were not left alone to protest peacefully.
Up till now, I've been fairly optimistic about a peaceful solution to the political tensions here, but now I'm not so sure. This is just the sort of senseless act of violence that could spark a civil war.
UPDATE: The AP has a wire story on the event, and apparently it was Sunnis who killed the Shia boy:
Violent clashes broke out Sunday between Shiite and Sunni Muslims in the capital, leaving one man dead from gunshot wounds at a time when tensions throughout Lebanon threaten the country's fragile sectarian and political balance.
...The clash in Tarik Jdideh occurred as a group of Hezbollah supporters were returning from Beirut's downtown and passed through the Sunni neighborhood.
Police officials said the two sides threw stones at each other, then shots were fired, killing Ahmed Ali Mahmoud, a 20-year-old Shiite. The officials spoke on condition of anonymity because they were not allowed to speak to the press.
At least 10 other people were slightly injured elsewhere in West Beirut in similar clashes.