Syrian tanks and troops stormed three districts of the central city of Homs and swept into several southern towns, in a campaign to crush an uprising against autocratic Baathist rule.
The official state news agency said an 'armed gang', a term used by authorities to characterise those involved in rebellion against President Bashar al-Assad, had ambushed a bus near Homs and shot dead 10 civilian workers returning from Lebanon.
In the first incursion into residential areas in Homs, Syria's third city, machinegun fire and shelling was heard across the city of one million people.
At least one civilian, a 12-year-old child, was killed when tanks and troops charged into the Bab Sebaa, Bab Amro and Tal al-Sour districts of Homs overnight, according to the Syrian Observatory for Human Rights.
The pro-democracy upheaval that began in Deraa on 18 March, inspired by similar revolts across the Arab world, spread on Friday across Hauran, an agricultural belt bordering Jordan to the south and the Israeli-occupied Golan Heights to the west.
Protesters are demanding political freedoms, an end to corruption and the departure of President Assad, who has said they are part of a foreign conspiracy to cause sectarian strife, an accusation the demonstrators dismiss.