The state bordering the US is among those hardest hit by drug related violence in Mexico.
Eight of the fatalities came in direct clashes with federal forces. The other death came in a fight between rival crime gangs, a statement from the Tamaulipas government said.
Tamaulipas, the main gateway from Mexico into the US, is enduring a wave of violence that has seen days in which more than a dozen people have been killed.
The fighting has been blamed on clashes between the Gulf and Zetas drug cartels, which were allies until 2010.