Syrian forces on Friday shelled a village near the border with Turkey, according to opposition activists, dpa reported.
"The Syrian security forces, backed by army tanks, shelled for three hours the village of Maaret al-Naaman in Idlib province," Omar Idlibi, a Lebanon-based Syrian activist, told dpa.
Maaret al-Naaman is believed to be a hub for army deserters.
Idlibi added that a government crackdown on overnight protests in the central province of Homs killed eight, raising the toll since Thursday to 20.
The opposition has, meanwhile, called for mass protests across Syria on Friday to urge foreign countries to expel Syrian ambassadors, a move they hope will isolate the regime of President Bashar al-Assad.
According to the United Nations, more than 3,500 people have been killed in Syria since pro-democracy protests began in mid-March.