According to Mexican authorities, a prison riot has left three police officers and one security guard dead.
On Tuesday, gang violence broke out in a Tamaulipas state prison, which claimed the lives of four security personnel as well as resulting in another six people sustaining injuries.
Television footage showed helicopters flying overhead, with concerned family members gathered outside the prison, as heavy gunfire was heard coming from the compound.
"State police are still inside and federal forces are giving support from the outside," a spokesman on security issues for Tamaulipas, Luis Alberto Rodriguez, said.
The city of Victoria in the state has been plagued by drug-related crimes. Turf wars between the rival Gulf Cartel and Zetas gangs have consumed the state for years and in recent times some of Mexico's worst drug violence has hit Tamaulipas.