(CNN) -- The grip of violence tightened in Ciudad Juarez, where gunmen fatally shot six people at a family reunion, Mexican officials said Saturday.
Police did not know whether the incident early Saturday was related to drug cartels or organized crime, according to Carlos Gonzalez, a spokesman for the Chihuahua state attorney general.
Seven gunmen entered the home, which was hosting a party of family and friends, in the Melchor Ocampo district, according to the state-run Notimex news agency.
Four men died at the scene and two other victims died later at a hospital.
Killings are all too common on this border city across from El Paso, Texas.
An official with the Chihuahua justice department was gunned down October 4. A drive-by shooting a few days earlier left a police officer dead and two others wounded.
August was the deadliest month so far in Juarez, with more than 300 killed, while about 230 people died in September from gang-related violence, Mayor Jose Reyes Ferriz said.
As the focal point for Mexican President Felipe Calderon's war on organized crime, Ciudad Juarez has had the misfortune of redefining urban violence. In 2009, more than 2,600 people were killed.
High-profile killings this year include the January killing of 15 people at a house party, most of whom were innocent students with no ties to organized crime; and the March killing of three people with ties to the U.S. consulate, who were on their way back from a children's birthday party. The female victim in that shooting was pregnant.
CNN's Nick Valencia contributed to this report.