Syrian security forces backed by tanks increased their efforts to control Jisr al-Shughour on Saturday, as the number of people who have fled from the border city into Turkey swelled to more than 4,000.

Witnesses and activists say soldiers appear to be sealing off the city, after the government accused “armed gangs” there of killing 120 security personnel and promised decisive action.

A state-run media report, Saturday, says army units have arrested “two leading groups of armed gangs” in the city. It says security forces seized weapons and explosives during the arrests.

On Friday, at least 32 people were killed as protesters across Syria rallied against President Bashar al-Assad's government. Activists say security forces opened fire on demonstrators in several cities.

They say seven protesters were killed in the town of Latakia as they tried to tear down a giant poster of Mr. Assad.

In Washington, the White House denounced what it said was Syria's “outrageous use of violence” in the government's three-month crackdown on pro-democracy protesters. The U.S. said Mr. Assad was leading Syria on a “dangerous path.”

At the United Nations, diplomats held new talks on a draft resolution condemning the violence, but failed to reach an agreement. Many Western nations support the measure, but Russia and China have voiced opposition.

U.N. Secretary-General Ban Ki-moon tried several times to call Mr. Assad, but U.N. officials said the Syrian leader has refused to take the calls. Later, Mr. Ban said the use of military force against civilians was “unacceptable,” and he expressed concern about the carnage.

Rights groups say at least 1,100 people have been killed in the Syrian crackdown that began in March and more than 10,000 people arrested.