Lebanese President Michel Sleiman on Thursday said his country opposed foreign military intervention in conflict-torn Syria, a day after fresh sectarian violence in north Lebanon raised fears of the crisis spilling over the border.

"I hope the Syrians, alone, can discuss and reach acceptable political solutions, far from any outbreak of violence, extremism or foreign military intervention," Sleiman, a former general, said at the start of a three-day official visit to Athens.

"The UN charter and decisions by international organisations must be respected," Sleiman said after meeting his Greek counterpart Karolos Papoulias.

There are mounting fears that Lebanon, where Syria has long held sway, could get drawn into the Syrian civil war.

Earlier on Thursday, security officials said snipers had killed eight people in the northern Lebanese city of Tripoli, which has been rocked by sectarian tensions linked to the nearly 21-month uprising against President Bashar al-Assad's regime in Syria.

Another seven people had been killed earlier in the week.

Sleiman made no comment on the Tripoli killings and took no questions.

Lebanon is deeply divided over Syria, with Shiite Muslim movement Hezbollah, its allies and supporters bitterly opposed to the revolt, and the Sunni-led March 14 movement backing it.

Syria deployed troops in Lebanon for nearly 30 years, until the 2005 assassination of former premier Rafiq Hariri prompted international outrage and forced a Syrian pullout.

Near-daily clashes in border areas inside Syria pit Shiite residents who support Hezbollah against anti-Assad rebels, residents and activists say.