Syrian state television is reporting the deaths of 120 security personnel in the northwestern city of Jir al-Shughour in what it is calling a "massacre."
The report could not be confirmed since foreign journalists are not allowed in the country. Syrian opposition activists are disputing the casualty count, suggesting it will serve as an excuse for a new government onslaught.
Syria's interior minister, Ibrahim al-Shaar, has pledged a "firm and decisive" response "in accordance with the law."
The area around Jir al-Shughour, near the border with Turkey, is the latest region to join an anti-government uprising aimed at ending the 11-year authoritarian rule of President Bashar al-Assad.
A government spokesman admitted that security forces have lost control of areas in and around the town.
Syria is blaming the unrest on armed terrorist gangs supported by foreign "agitators."
Rights groups say at least 1,100 people have been killed in the government's crackdown against the anti-government campaign that began in March. More than 10,000 have been arrested.
Some information for this report was provided by AP, AFP and Reuters.