On Monday, intermittent gunfire was heard as troops launched search operations in the village of Uram al-Joz, east of Jisr al-Shughur and in the Jebel al-Zawiya mountains further south, the activists said.
The majority of the town's 50,000 residents had fled in the week-long build-up to the crackdown.
More than 6,800 have sought refuge in Turkey, some 40 kilometres (25 miles) from the town, Turkey's Anatolia news agency reported.
A further 5,000 have fled to Lebanon, the United Nations said.
France's UN ambassador Gerard Araud said that diplomatic wrangling at the UN Security Council over a draft resolution condemning the Syrian crackdown, which has now gone on for two weeks, was costing lives.
UN SLOW TO ACT
"In that time 400 people, including women and children, have died, sometimes under torture," he said. "Thousands of refugees have fled Syria."
The United States is backing the European draft but veto-wielding Security Council permanent members Russia and China have so far blocked it, and several non-permanent members have expressed reservations.
White House spokesman Jay Carney said that Washington condemned the violence being perpetrated in Syria "in the strongest possible terms."
"A transition needs to take place. If President Assad does not lead that transition then he should step aside," Carney said.
But State Department spokesman Mark Toner ruled out any recourse to Libya-style military action for the time being. "We're just not there yet," he said.
Some of those who have made it across the border into Turkey described how the Syrian army had embarked on a scorched earth policy in Jisr al-Shughur and other villages in Idlib province, which has long been a hotbed of hostility towards the Damascus government.
But while some troops had appeared to be bent on destruction, others tried to defend the townsfolk and battles flared among the army on Sunday when parts of a tank division defected and then set up base by bridges into the town, they said.
'TROOPS DIVIDED'
"The troops are divided. Four tanks defected and they began to fire on one another," said 35-year-old Abdullah, who fled Jisr al-Shughur on Sunday and sneaked over the border into Turkey in order to find food.
Ali, another Syrian refugee who made it to Turkey, also described evidence of a rift within the ranks.
"There is now a split within the army and you have a group who are trying to protect the civilians," the 27-year-old told AFP.
Abdullah, who like many refugees would give only his first name, said that troops had now reached Ziayni, a town just six kilometres (four miles) from the Turkish border.
"They torched all the crops, they slaughtered the goats, the cows," he said.
"In the town itself, all the bakeries and the supermarkets have been pillaged, there is nothing left. The doors have been smashed in," he said.
He said that there was a sectarian bias to the army's crackdown with troops focusing on villages of the Sunni Muslim majority and leaving those of the president's minority Allawite community untouched.
"The soldiers did not approach the Allawi villages. They only attacked Sunni villages, and destroyed them," Abdullah said.
Syrian state media said that an official inquiry into an earlier crackdown on anti-government protests in the Daraa region south of Damascus had ruled that two senior officials - one a cousin of the president -- should be barred from going abroad pending further investigation.
The bans affect Ateb Najib, Assad's cousin who headed security in Daraa, and Faisal Kulthum, the town's former governor.
Protests erupted in Daraa and then spread around the country after 15 students were arrested on suspicion of writing anti-government graffiti around the town.
Daraa residents said the students were tortured and their fingernails extracted.
