Syria's government has vowed to deal "decisively" with the gunmen blamed for the deaths of 120 security personnel in the northern town of Jisr al-Shughour.
Interior Minister Ibrahim Shaar said the state would act "with force".
Residents later warned that there would be massive bloodshed if the authorities attempted to restore control by force.
Meanwhile, France says it is ready to ask the UN Security Council to vote on a draft resolution condemning Damascus, despite a likely Russian veto.
Speaking in Washington, French Foreign Minister Alain Juppe said Paris believed that strong support in the 15-member Council might persuade the Russians "to change their mind".
"We think that it will be possible to get 11 votes in favour of the resolution and we'll see what the Russians will do," he said.
The draft resolution was drawn up by France, Britain, Germany and Portugal, the AFP news agency reports. The document condemns violence at the hands of the regime of Syrian President Bashar al-Assad and asks him to open Syrian cities to humanitarian teams.
On Monday, in a dramatic series of urgent flashes, state television said hundreds of gunmen had taken over Jisr al-Shughour, which lies about 20km (12 miles) from the Turkish border, and had committed "a real massacre".
A report said the fighting had begun at dawn, when "armed gangs" ambushed police as they approached the town "to rescue citizens being terrorised". Twenty officers reportedly died.
It said another 82 personnel were killed when the town's security headquarters were overwhelmed, and eight in a bomb attack on a post office they were guarding.
Many government buildings were attacked and burned, causing further casualties, it added. The overall death toll for security forces was put at 120.
"We will deal strongly and decisively, and according to the law, and we will not be silent about any armed attack that targets the security of the state and its citizens," said Mr Shaar in a statement read on television.
Information Minister Adnan Mahmoud said army units, which have so far stayed out of the town, would "carry out their national duty to restore security".
Later, a statement published on one of the Syrian uprising's main Facebook pages in the name of the people of Jisr al-Shughour denied that they had called for army intervention to protect them from armed gangs.
It condemned the reported deaths of dozens of security personnel in the town and called for an immediate and transparent inquiry.
The statement said the people feared a crime against humanity would be committed if Syrian army tanks moved in to regain control.
More civilians would inevitably be killed and thousands would flee their homes if the tanks come in, it warned.
An Islamist uprising in Jisr al-Shughour in 1980 against the late President Hafez al-Assad was brutally crushed with scores of deaths.
The protesters continue to insist that the movement is entirely peaceful, and to scorn the government's talk of armed gangs.
But government officials, like spokeswoman Reem Haddad, are adamant that groups of gunmen are behind the killing.
"I wouldn't count them as civilians because civilians are people who carry no arms," she told the BBC World Service.
"These people are dead and we have bodies with names and dates of birth. It's not something that the Syrian government has invented. They have families, mothers and fathers, and sons and daughters."
The BBC's Jim Muir in Beirut reports that protesters say some army personnel may have deserted to join the uprising.
"The soldiers were coming our way. Then they were shot in the back by some Syrian security elements," one resident told BBC Arabic.
There is even speculation of a mutiny at the security headquarters, and that personnel who refused to fire on demonstrators were executed.
Communications were cut to the area around the town on Monday and the details of the attack were impossible to verify.
But whatever the truth, the events in Jisr al-Shughour represents a massive challenge to the government, our correspondent says.
Before Monday, the government said more than 160 security forces personnel had died since the uprising began in mid-March. Human rights activists meanwhile said that more than 1,200 people had been killed.