Gunfire erupted at a Venezuelan prison on Tuesday, prompting National Guard troops to use tear gas as they sought to take back control from armed inmates.

Venezuela's government is trying to close La Planta prison, following two escape attempts and complaints of overcrowding, saying the facility doesn't meet standards. Half the prison's inmates have already been transferred to other lockups.

Top prisons official Iris Varela said Tuesday that a small group of inmates has been resisting being transferred. She said several shots were fired from inside the prison.

Dozens of troops in anti-riot gear gathered outside, and clouds of tear gas floated in the air over the prison.

Hundreds of prisoners' relatives, worried by the gunfire, stood outside. Some of them wept.

Varela appealed for calm. She urged the resisting inmates to "give up their violent attitude, listen to their relatives."

"We know there are some who are resisting the evacuation," Varela said on state television. "However, they aren't right to be acting in that violent way."