Syrian troops shot dead four villagers on Wednesday, an activist said, as authorities pressed on with a tank-led assault that has already driven thousands of refugees across the northwest border with Turkey. "The four died in random firing on the village of Rama from tank machineguns, which has become customary in these unjustified assaults. The tanks started firing on surrounding woods then directed their fire on the village," Ammar Qarabi, president of the Syrian National Human Rights Organization, told Reuters from exile in Cairo. The assault on Jabal al-Zawya, a region 35 km (22 miles) south of Turkey that has seen spreading protests against Assad's 11-year rule was launched overnight, a day after the authorities said they would invite opponents to talks on July 10 to set a framework for a dialogue promised by President Bashar al-Assad.