Gunfights and blockades of burning vehicles broke out Friday in the border city of Reynosa, across from McAllen, Texas, leaving at least three dead, Mexican authorities said.
The government of the border state of Tamaulipas said federal police and soldiers had "detained members of a criminal gang that operates in Reynosa," an apparent reference to Gulf cartel members.
"Members of the same criminal group reacted (to the arrests) by attacking federal forces and carrying out blockades in the city," the statement said.
Officials said roads in the city were blocked with vehicles set on fire by gunmen.
The state government said three armed civilians, presumably cartel gunmen, had been killed in the confrontations. Authorities said the situation was brought under control by late afternoon.
The detained gang members were taken to Mexico City, the state government said.
A state official who was not authorized to be quoted by name confirmed reports that a top member of the Gulf cartel's Reynosa faction had been detained. The gang leader has been known by his nickname "El Gafe," but his real name could not immediately be confirmed. The nickname apparently refers to a now-disbanded Mexican special forces military group.
The U.S. consulate in Matamoros issued a message urging U.S. citizens to take precautions because of "several firefights and roadblocks throughout the city of Reynosa." The city government posted a warning on its Twitter site recommending motorists avoid several areas, including the highway leading to the nearby city of Matamoros.
Warring factions of the Gulf cartel in Reynosa and Matamoros, known as the Metros and the Ciclones, have been fighting turf battles around the two cities.