The Syrian army has begun operations to "restore security" to the town of Jisr al-Shughour and the surrounding area, state TV says.Earlier in the week, the Syrian government said 120 security personnel were killed in the north-western town.
The announcement, and the positioning of troops in the area, has prompted a flow of refugees to nearby Turkey.
The government has blamed the deaths on armed groups, but there are reports of a mutiny among security forces.
Syrian state TV said armed men were in control of the town and had prepared defences.
The Turkish government says more than 2,000 Syrians have crossed the border seeking refuge from the anticipated crackdown in Jisr al-Shughour.
Conflicting accounts Syria has prevented foreign journalists, including those from the BBC, from entering the country, making it difficult to verify reports from there.
The BBC's Jim Muir, in Beirut, Lebanon, says the events in Jisr al-Shughour present a massive challenge to President Assad.
Syrian state TV has been preparing the way for the security operation in the town and in anticipation
The reported action against Jisr al-Shughour is in response to claims by Damascus that armed gangs killed 120 members of the security forces there after protests against President Assad's rule.
The government says local residents requested the army's intervention to restore peace and quiet.