Mexican authorities say gunmen in vehicles opened fire in the city of Reynosa on the US border, killing at least 18 people and causing widespread panic
Security forces killed four of the gunmen, including one who died near a border bridge, the AP is reporting.
The attacks began on Saturday afternoon in several neighbourhoods in Reynosa, which borders the Texas city of McAllen, according to the Tamaulipas state agency that coordinates security forces.
Images posted on social media showed bodies in the streets.
Tamaulipas Governor Francisco García Cabeza de Vaca on Sunday condemned the loss of “innocent civilian” lives and said the motive for the attack will be investigated.
The area’s criminal activity has long been dominated by the Gulf Cartel, but there have been fractures within the group.
Reynosa Mayor Maki Esther Ortiz Domínguez said city residents must be protected.
The Mexican army, National Guard, state police and other agencies mobilised after the shootings.
During the security sweep, authorities said they detained a person who had two women, apparently kidnapped, in the trunk of his car. They also seized three vehicles.
Reynosa is a key crossing point for migrants attempting to reach the US.
The border area and nearby towns and villages are choked with would-be migrants waiting to cross illegally into the US.
There are several factors at play in the migrant surge, says CNN, including deteriorating conditions in Latin America, pent-up demand to enter the US and a perceived relaxation of enforcement under President Joe Biden.