Syrian tanks and troops have sealed the restive northern town of Jisr al-Shughur with activists saying they expect an all-out government assault soon.
President Bashar al-Assad sent heavy armour, including tanks and thousands of troops, to the region to crush a nearly three-month uprising against his family's 40-year rule.
Saturday's military operation close to the Turkish border is in response to what the government claims were attacks by "armed groups" that killed more than 120 officers and security personnel last week.
Syrian state television said troops had arrested several leaders of the alleged armed groups in Jisr al-Shughur.
The troops backed by dozens of tanks have been operating in the area for several days, securing towns and villages on their way to the northern Syrian town.
Jamil Sadeq, a resident of the town, accused the troops of intermittently opening fire.
"The army entered with tanks and used heavy weapons on the villagers. They then fled into the mountains," he told Al Jazeera.
"A second village was also attacked. The regime is attempting to regroup a military brigade there. Elsewhere in nearby villages there are shootings every half hour.
"To the east, the army stormed villages on the way to Ziyaara with tanks and reached there in the early morning. Residents fled ... either to the north or towards Turkey where the main [refugee] camp is."
Syria warning to UN
The Syrian crackdown on anti-government protests have invited global condemnation, but Damascus on Friday rejected all criticism.
It warned the United Nations that a European draft resolution condemning the country for the crackdown would only embolden "extremists and terrorists".
"It is important that the Security Council should not intervene in the internal affairs of Syria, which is a founding member of the United Nations," Syrian Foreign Minister Walid al-Moualem told the UN Secretary-General Ban Ki-moon in a letter obtained by Reuters news agency on Friday.
"We are quite certain that any resolution that is adopted by that body under any heading will only exacerbate the situation and send a message to those extremists and terrorists to the effect that the deliberate destruction that they are wreaking has the support of the Security Council," he said.
In-depth coverage of escalating violence across Syria
The Syrian response came as UN Security Council diplomats met in New York in another attempt to break their deadlock on a draft resolution that would not impose sanctions on Syria but would condemn it for the crackdown and suggest Syrian security forces might be guilty of crimes against humanity.
Al-Moualem offered no apology for the crackdown, which rights groups say has killed at least 1,300 civilians since March. He said Damascus had no choice but to press ahead to ensure "the security of the nation and the population".
"We hope that the United Nations and its member states will assist Syria in confronting the challenges of extremism and terrorism and will not hastily adopt a position that will provide a cloak for the murderous, destructive gangs," he said in the letter.
He said that diplomatic moves to condemn Syria "constitute flagrant intervention in the internal affairs of Syria and an attempt to destabilise it and control the current and future decisions and destinies of its people".
Despite Syria's protestations, the White House significantly toughened its stance on Friday, calling for an "immediate end to brutality and violence".
The White House spokesman Jay Carney, in a statement, said President Assad was leading his nation on a "dangerous path".
|About 4,000 Syrians have fled across
the border to Turkey [Reuters]
The renewed criticism came as Syrian activists said that 32 people were killed, many of them after troops shelled the northwestern town of Maarat al-Numan, 40km from Jisr al-Shughur, on Friday.
Anti-government protests were held in many cities across the country after Friday prayers.
Security forces shot dead two protesters when they fired at a rally in the Qaboun district of Damascus, the London-based Syrian Observatory for Human Rights said.
The group said nine protesters were also killed in the Mediterranean port city of Latakia.
A resident in Deraa, in the south of the country, told Al Jazeera that two protesters had been killed there.
Security forces also shot dead two civilians in a village in the southern Hauran Plain, residents said.
About 4,000 Syrians have fled into neighbouring Turkey to escape the unrest in Jisr al-Shughur and other towns, according to the UN and Turkish officials.
Lebanon, Syria's neighbour to the west, has already absorbed about 5,000 refugees, though the UN says it is a "fluid population" and some of the refugees have already returned home.
A UN spokesperson said that Ban Ki-moon had been trying to call the Syrian president all week but was told that he was "not available."
Robert Ford, the US ambassador in the Syrian capital, Damascus, has also seen his requests for meetings with Syrian government officials repeatedly denied.