Shots against the consulate and Mexican military premises were reported amid gunfighting and pursuits in parts of the city that lies opposite Laredo, Texas, the ministry of public security in the state of Tamaulipas said in a statement, according to Reuters.
Suspected gang members paralyzed traffic in Nuevo Laredo early Monday by blocking roads with spike strips and setting fire to trailer trucks, the statement said.
The US consulate advised its employees to stay indoors and urged US citizens to do the same or avoid the area. The consulate will be temporarily closed to the public, the Mexican government said later in a statement.
A senior Tamaulipas official told Reuters there was at least one "collateral" fatality due to the violence.
The gunfight followed the arrest of Juan Gerardo Trevino, or "El Huevo," on Sunday, Mexico's government said in a statement.
Trevino is facing a US extradition order for drug trafficking and money laundering, as well as state-level charges for murder, terrorism, extortion and criminal association, it added.
He is also a US citizen, a Mexican government official told Reuters. Trevino is on a list of the US Border Patrol's most wanted criminals, according to media reports.
MP/PR