Syrian forces killed at least one civilian on Monday in raids on villages near Turkey designed to stop civilians fleeing across the border to escape a military crackdown on popular unrest, residents and local activists said.

Adelsalam Hassoun, 24, a blacksmith, was killed by army snipers just after he had crossed into Turkey from the village of Ain al-Baida on the Syrian side, his cousin told Reuters by telephone from Syria.

"Abdelsalam was hit in the head. He was among a group of family members and other refugees who dashed across the plain to Turkey when six armoured personnel carrier deployed outside Ain al-Baida and started firing their machineguns into the village at random this morning," Mohammad Hassoun said.

It was the first large-scale military operation in the border region since June, when thousands of families fled their homes as troops assaulted numerous town and villages that had seen big protests against President Bashar al-Assad.

Another witness said Syrian forces backed by armour also entered the town of al-Janoudiya northwest of Ain al-Baida after security police fought pitched gunbattles with a small group of army deserters attempting to flee to Turkey.

"They are trying to prevent every one, civilians and deserters, from reaching Turkey. We have seen over the last week more refugees trying to make the border after the attacks on Latakia and Hama and Homs provinces," said Bashar, a resident of Janoudiya.

Most army conscripts are from Syria's Sunni Muslim majority and many come from rural areas targeted in military efforts to crush six months of protests against Assad.

Army commanders and security chiefs are mostly from Assad's minority Alawite sect, an offshoot of Shi'ite Islam.