Gun battles rock Mexican border city

Gunfights erupted in broad daylight Friday in a Mexican city across the US border plagued by drug cartel violence and several vehicles, including a school bus, were set on fire.

There were no immediate reports of casualties from the clashes in Reynosa, a city of 610,000 located across from the Texas town of McAllen, but a US consulate warned Americans to keep off the Reynosa streets.

Mexican authorities suspect the gun battles, which began in the early afternoon, are related to a power struggle within the Gulf cartel, an official in the Tamaulipas state prosecutors office told AFP.

"We don't know if there are victims because we can't reach the locations (of shootings) for the moment," the official said.

Gunmen blocked streets with vehicles, setting several ablaze, including a school bus, the official said. The tactic is used to prevent rival factions or government forces reaching the area.

The local daily El Manana reported that US authorities temporarily closed two border crossings.

The US consulate in the city of Matamoros, which oversees consular affairs in Reynosa, issued a message saying it "has learned of several firefights and roadblocks throughout the city" and urged Americans to "use extreme caution and to remain in-doors."

Reynosa residents posted pictures on Twitter of burning vehicles and people lying on the ground in panic.

The government has dealt blows to the Gulf cartel in recent years with the arrest of several leaders. Authorities have blamed a surge of violence in Tamaulipas this year on the gang's infighting.

The gang has also battled its former allies, the Zetas cartel, for control of drug trafficking in Tamaulipas.