Ciudad Juarez, Mexico -

The violence in El Paso's sister city keeps getting worse. Thirteen people were killed late Friday night when gunmen stormed into a Ciudad Juarez neighborhood and fired into a crowd of party-goers at a teenager's birthday celebration.

Chihuahua state officials say seven men and six women died after the mass shooting, which took place in two adjacent homes in the Horizontes del Sur neighborhood.

Twenty other people were wounded, including a 9-year-old boy.

"It's pretty scary, you know," said El Paso resident Rene Picarro. "You're at a party celebrating something and then having people come into your house and just shooting at everybody."

Picarro told ABC-7 he visits Ciudad Juarez daily to visit family and is afraid for their safety. "I just wish I had the money to bring them over here," he said.

A Ciudad Juarez grandmother who was crossing the border into El Paso to drop off her grandchildren said people in her neighborhood live in constant fear of cartel-related violence. "People in Juarez are no longer safe in their own homes," she said.

Friday night's massacre is the third attack of its kind in Ciudad Juarez so far this year. Last Sunday, nine people died in a separate shooting at a family party. Earlier this year, another massacre took place.

And in January, 16 people, mostly teenagers, were killed by gunmen in Colonia Villas De Salvarcar. Villas de Salvarcar is only about a mile from the Horizontes del Sur neighborhood, the scene of Friday night's shooting.

In all three cases the gunmen took off before authorities arrived. Police have been able to arrest suspects only in connection to January's massacre and they have not identified a clear motive for any of the killings. The massacres do not appear to be directly connected.

Back at the U.S.-Mexico border, Picarro said he dreams of a safer Ciudad Juarez, but adds he can do little to make that dream become a reality in the face of the city's brutal cartel-fueled war.

"I just pray to God that they'll give us our Juarez back," he said.