Police in Mexico say major roads in Monterrey were blocked by members of a drug cartel on Saturday.
Drivers were dragged out of their vehicles by armed men and their cars used to shut at least 13 roads.
The BBC reports the blockade happened after a shootout between the army and suspected members of a drug cartel. Four were killed.
Police say the cartels blockade the streets as a show of force.
Security forces said the shootout happened in the south of the city, after soldiers on patrol chased two armoured cars that they considered suspicious.
One of the vehicles crashed and its occupants opened fire on the troops.
Four of them were shot as they tried to flee. A fifth escaped.