MEXICO CITY (REUTERS) - A US citizen suspected of involvement in the brazen daylight shooting of a US consular official in the Mexican city of Guadalajara was arrested on Sunday (Jan 8), the government said.

The unnamed man will be extradited to the United States, where his legal status will be determined, Mexico's foreign ministry and attorney general's office said in a joint statement.

A video posted online by the consulate in Guadalajara, Mexico's second-largest city, shows the shooter on Friday afternoon appearing to wait for the official's car to pull up to a parking lot barrier before firing directly at the driver and then fleeing.

A source told Reuters the consular official had been shot in the chest. A motive was not disclosed.

The statement said Mexican federal authorities continued to investigate the "cunning and cowardly" shooting in collaboration with their US counterparts.

The Jalisco state prosecutor said earlier on Sunday that special agents made the arrest but did not provide further information about the suspect.

The consular official was later identified as Mr Christopher Ashcraft by a Mexican security official speaking on condition of anonymity. Mr Ashcraft remained in stable condition at a local hospital.

US Secretary of State John Kerry thanked the Mexican government for the "swift and decisive arrest of a suspect in the heinous attack against our Foreign Service Officer colleague," according to a statement on Sunday.

The US Federal Bureau of Investigation had offered a reward of US$20,000 (S$28,797) for information that helped to identify the shooter.

Guadalajara and surrounding areas have often been the scene of violence by rival drug gangs.