A weeklong truce was shattered early Tuesday when Moslem militiamen, backed by Syrian gunners, exchanged artillery fire with Christian forces in and around Beirut, police said.

The latest flare-up came hours after the United Nations called on the warring factions to end six weeks of bloodshed and on the eve of a conference of Arab foreign ministers in Tunis, Tunisia, on solving the worsening conflict.Initial casualty reports said one person was killed and 13 others wounded in the latest fighting Tuesday.

The clashes ended a seven-day lull in violence that has claimed at least 268 lives since March 13.