Activists reported tanks in the northern town of Maaret al-Numan and other villages near Jisr al-Shughour a town that was retaken Sunday by Syrian 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 Iraqi border, where the Syrian government claimed to have thwarted weapons smuggling.
Some analysts have said President Bashar Assad is trying to keep the opposition from establishing a base, which happened in Libya when the rebels trying to overthrow Moammar Gadhafi 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 swaths of the country, the government has abandoned most pretense at reform.
Most of the major military operations have been in border areas such as Jisr al-Shughour, the southern city of Daraa near the border with Jordan and central province of Homs that borders Lebanon.
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. About 8,500 have fled to Turkey, where they offer a frightening picture of life at home.