Syrian troops shelled two northern villages overnight after an attack by army defectors on forces loyal to President Bashar al-Assad, local activists said on Friday, in the first reported use of sustained shelling against the eight-month uprising.
The assault came a day after the Arab League suspended Syria and gave it until the end of the week to comply with an Arab peace plan to end a crackdown on the revolt that has killed more than 3,500 people, by a United Nations count.
Along with mostly peaceful street protests demanding Assad's removal, an armed insurgency has emerged, prompting calls by opposition leaders for protesters to stick to non-violence in face of an escalating crackdown.
Eight villagers were injured overnight when tank shells and heavy mortars fell for three hours on Tal Minnij and Maarshamsheh and surrounding farmland, the activists said.
"Hundreds of families have left. Electricity and Internet services have been cut off," said one of the activists who gave his first name as Raed.
It was not possible to confirm the shelling independently. Syria has barred most foreign media since unrest began.
The official news agency said troops carried out a "qualitative operation" in the region, arresting 58 wanted people and seizing rifles and bomb detonators.
Until now, Syrian troops mostly have been using heavy machineguns and anti-aircraft guns, employed as a ground weapons, on restless cities and towns to try to put down the uprising.
Army defectors earlier had attacked a building housing security forces near army depots in the Wadi al-Deif area on the edge of the town of Maarat al-Numaan, 290 km (180 miles) north of Damascus, activists said.
The town, on the Damascus-Aleppo highway, has seen regular street protests demanding Assad's removal and raids by security forces to put down the demonstrations.
In the last few weeks, residents say a growing number of army defectors has been defending Maarat al-Numaan and attacking army patrols and roadblocks. One resident said the town's main hospital received 40 troops and security forces between dead and wounded on Wednesday.
Among them was activist Samer al-Tayyeb, who was arrested in house-to-house raids in the eastern province of Deir al-Zor and died in custody, the main activists group known as the Local Coordination Committees said.
The authorities blame the violence on foreign-backed armed groups who they say have killed more than 1,100 soldiers and police.
The official news agency said eight "of the most wanted terrorist" were arrested on Thursday in the central city of Homs, where tanks have been deployed.
While Arab and Western countries sought to pile pressure on Assad, Russia, which has a naval base, major oil concessions and military personnel in Syria, stood by him.
Russian Foreign Minister Sergei Lavrov, whose country is one of Syria's few remaining foreign friends, said demands for Assad's removal would destroy the initiative, which calls for dialogue between the Syrian government and its foes.
Lavrov said a raid on Wednesday by the Free Syrian Army on an Airforce Intelligence complex on the outskirts of Damascus was "already completely similar to real civil war".
Opposition sources said Syrian army defectors had killed or wounded 20 security police in the early-morning attack, the first of its kind in the revolt against Assad.
U.S. State Department spokesman Mark Toner rejected the suggestion that Syria was virtually in civil war, saying: "We believe it's very much the Assad regime carrying out a campaign of violence, intimidation, and repression against innocent protesters."
Syria's pervasive security apparatus, dominated by Assad's minority Alawite sect, underpins the power structure that has enabled Assad, and before him his father, to rule for 41 years.
While the West appears to have no appetite for military intervention in Syria, a leader of Syria's outlawed Muslim Brotherhood said Turkish military action might be acceptable.
Mohammad Riad Shaqfa said this week's attack on the security complex near Damascus was carried out by soldiers "who have refused orders to kill their own people".
"We reaffirm the peacefulness of the uprising," Shaqfa said. "We are calling on civilians not to take up arms."