Syrian tanks were reported to be pushing toward more towns and villages near the border with Turkey today.
As the government expanded its crackdown on dissent, activists said tanks had entered the northern town of Maaret al-Numan and other villages near Jisr al-Shughour - a town that came under a military siege on Sunday by elite forces backed by helicopters.
Human rights activist Mustafa Osso said tanks were also moving in the eastern province of Deir el-Zour on the border with Iraq.
Activists say more than 1,400 Syrians have died and some 10,000 have been detained in the government crackdown since the popular uprising began in mid-March.
Thousands have fled to Turkey, where they offer a frightening picture of life at home.
Some analysts believe President Bashar Assad is trying to keep the opposition from establishing a base, which happened in Libya when the rebels trying to overthrow Muammar Gaddafi took over the coastal city of Benghazi.
Assad initially had promised mild reforms, but his appeals have been rejected by the thousands of protesters who say they will not stop until he leaves power, ending his family's 30-year regime.
And in the past week, as the government appeared to be on the verge of losing control of major swathes of the country, the government has abandoned most pretence at reform.
Among the refugees was Mohammad Hesnawi, a 26-year-old from Jisr al-Shughour.
In the Syrian border village of al-Hasaniya, he said, Turkish authorities have given priority to women and children who want to flee.
"People in al-Hasaniya are eating fruit out of the trees, including apples and cherries," he said, adding that there was not enough for everyone.
He accused pro-government militias known as Shabiha of atrocities in Jisr al-Shughour. "They damage homes and buildings, kill even animals, set trees and farmlands on fire," Hesnawi said.
Turkey's prime minister has accused Assad's regime of "savagery," but also said he would reach out to the Syrian leader to help solve the crisis.
Turkey and Syria once nearly went to war, but the two countries have cultivated warm relations in recent years, lifting travel visa requirements for their citizens and promoting business ties.