The suspected gunmen were traveling in two vehicles when they entered a scrap business on 5 de Mayo street in the San Ángel Norte neighbourhood.
The victims included three children, aged 14, 15 and 16 years, two adult males, aged 19 and 25, and a woman aged 20. As well, a man named Julio Cesar Campos Vasquez, 19, was seriously injured and taken to the nearby Hospital Universitario, which is slightly northwest of downtown.
As is typical in such situations, Mexican authorities responded at all levels, with local, state and federal police on the scene, as well as the armed forces.
One of the vehicles used by the gunmen had been stolen, and was found abandoned shortly after the attack.
Monterrey is located in territory disputed by the Gulf Cartel and Los Zetas. Since the beginning of this year the gang war has intensified, leaving at least 150 people dead.
February 11, 2013: Video reveals startling daylight battle in Reynosa that leaves five dead