Feuding Mexican cartels briefly blocked roads Tuesday in the border city of Matamoros, across from Brownsville, Texas.

At one point, gunmen forced middle-school students off a school bus and used the vehicle as a blockade.

Roads were quickly cleared and officials claimed that one death reported early Tuesday morning was not related to the blockades.

At about a dozen points in and around the city, gunmen carjacked vehicles and left them parked across roadways. The military deployed about 700 troops and two helicopters to quell the violence.

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Officials in the northern state of Tamaulipas said the blockages were caused by battles between two rival cartels. Matamoros has long been dominated by the Gulf cartel, but it has splintered into warring factions, one of which is reportedly allied with the Jalisco cartel.

State police chief Sergio Hernando Chávez told local media that "there was a confrontation between rival organized crime groups."

He said all the children aboard the hijacked bus were unharmed.

On Monday, in the same area, police said they had arrested a top lieutenant of the violent Metros faction of the Gulf cartel implicated in 23 attacks on police and nine against military personnel.