Syrians in their thousands took to the streets nationwide for the 17th consecutive Friday to demand an end to Assad's 11-year rule, activists said, by telephone, defying an intensifying military crackdown on an uprising for political freedoms.
Security forces shot dead a civilian when they fired at demonstrators in the southern village of Museifra, rights campaigners said.
They added that demonstrators came under fire in the nearby city of Deraa, cradle of the uprising, in the coastal cities of Banias and Latakia, and in the Damascus suburb of Hajar al-Assad, mostly inhabited by refugees from the Israeli-occupied Golan Heights.
The official Syrian news agency said a member of the security police was killed in the town of Albu Kamal on the border with Iraq, and that saboteurs bombed an export oil pipeline near the central city of Homs on Friday,
The attack caused an oil leak, it said. Homs hosts one of Syria's two oil refineries and has been hit by big street protests. Assad has deployed tanks in Homs.
Syrian authorities have expelled most independent journalists since the uprising began, making it difficult to verify reports of clashes, and do not usually comment on reports of killings.
"Our main goal is the downfall of the regime," a preacher told worshippers at the central Orontes Square in the city of Hama, scene of a massacre by the military in the 1980s.
Popular unrest against four decades of repressive rule by the Assad family, now in its fifth month, is taking on sectarian overtones with protesters from the Sunni Muslim majority pitted against minority Alawites dominating the power elite.
Military intelligence, in charge of securing loyalty to Assad among the army's mostly Sunni rank and file, has been spearheading a crackdown in Syria's Sunni tribal east, a strategic oil-producing region near the border with Iraq.