|There have been numerous deadly gunfights between soldiers and drug cartels in recent months [GALLO/GETTY]
Attackers have killed a retired army general who took over a month ago as police chief of the violence-wracked Mexican border city of Nuevo Laredo.
The government of northern Tamaulipas state said on Thursday that two of Manuel Farfan's bodyguards also were killed and two more suffered wounds in the attack.
Farfan, the city's public safety chief, was attacked late on Wednesday, the office of Morelos Canseco, the Tamaulipas interior secretary, said in a statement. It did not indicate who was suspected.
Nuevo Laredo, across the border from Laredo, Texas, has been the scene of bloody drug-gang turf battles.
Farfan had received telephone threats since taking over as the city's highest-ranking public-safety official on January 1.
One of the two dead bodyguards was also a retired army officer like Farfan. Military officers have been recruited in many northern Mexico cities to reform and discipline weak or corrupt local police forces.
In another development, Mexico's federal government announced on Thursday an agreement to provide more than $41.5m for public safety and law-enforcement programmes in northern Chihuahua state, home to the violent border city of Ciudad Juarez.
Ciudad Juarez, across from El Paso, Texas, recorded more than 6,000 drug-related killings in 2009 and 2010, making it one of the cities with the highest murder rates in the world.
In previous days, suspected drug gangs have targeted Mexican police and marines in various cities in a series of co-ordinated attacks.