TRIPOLI, Lebanon (Reuters) - Lebanese supporters of rival factions in Syria's civil war battled overnight in the city of Tripoli in the worst such bout of spillover violence since the conflict started two years ago. One person was killed and many were wounded as Sunni and Shi'ite Muslim gunmen fired mortar bombs and rocket-propelled grenades at each other in a fifth day of clashes in the coastal city, security sources said on Wednesday.

Ending months of hesitation, the European Union opened the door Tuesday to adding the military wing of Lebanon's Hezbollah to its list of international terrorist groups, EU diplomats told AFP. A formal request to blacklist Lebanon's most powerful political and military group was filed by Britain and is to be discussed at closed-door talks June 4 of a committee overseeing the EU list of people and groups subject to its asset freezing regime. "We hope to have an agreement by the end of June on Hezbollah," said a diplomat close to the matter who spoke on condition of anonymity.

Elite Hezbollah fighters poured across the border from Lebanon into Syria on Tuesday, a watchdog and others said, bolstering Syrian regime forces battling to retake the key rebel stronghold of Qusayr. Washington condemned Hezbollah's direct intervention on the side of President Bashar al-Assad's regime and diplomats said the European Union was poised to place the Shiite militant group's military wing on its terror blacklist.

By Dominic Evans BEIRUT (Reuters) - Syria said its troops destroyed an Israeli vehicle that crossed into its territory from the Israeli-occupied Golan Heights on Tuesday and warned that any attempt to violate its sovereignty would meet "immediate and firm retaliation". Israel said the incident took place on its side of the Golan ceasefire line, that the vehicle was damaged but not destroyed, none of its soldiers were hurt and they returned fire.