Two United States officials and two Mexican law enforcement officers were killed in a car crash in Chihuahua, Mexico, while on an operation targeting drug cartel activity.

The Mexican officials were identified as a senior investigation agency director and an officer working on dismantling illegal drug laboratories.

US officials have not yet been publicly named, but they were part of a joint security effort.

US and Mexican authorities described the deaths as a reminder of the risks faced in combating organized crime, The Guardian has reported.

Officials in Chihuahua and the US embassy expressed condolences and pledged to continue their security cooperation.