A student watches for security forces near a protest barricade at dawn in San Cristóbal, Venezuela, March 9, 2014. John Moore/Getty Images

SAN CRISTOBAL, Venezuela — Venezuela’s national guard launched a late-night assault Sunday and into Monday in the western city of San Cristóbal, considered the birthplace of recent protests against the country’s government.

Armored cars smashed barricades as guardsmen launched volleys of tear gas against protesters in a northern section of the city, a middle- to upper-middle-class neighborhood.

The area is known as a hotbed of political opposition to President Nicolás Maduro, and its residents have sparred with government forces for more than a month, hurling stones and Molotov cocktails at security forces.

Demonstrations began here last month after students marched in protest over what they described as the police’s failure to respond to a sexual assault on campus, but the protests later spiraled into nationwide calls for broader social and economic reforms.

“No one realizes what is happening here,” said Ricardo Alvarez, a San Cristóbal resident who has been protesting against the government since mid-February.

Barricades were erected across the area in an effort to restrict access of government forces and armed gangs. But in the blocked-off hillside neighborhoods, sounds of tear gas canisters being fired could be heard throughout the night.