Mexican police launched a manhunt for a gunman who shot and wounded a US consulate official who was driving out of a parking garage in the western city of Guadalajara.

The consulate posted a video on Facebook showing the attacker, dressed in blue, waiting outside a shopping centre's garage on Friday, raising his gun and firing at the car before fleeing.

"An official from the US consulate was wounded by a shot from a firearm ... According to the medical report, he is in stable condition," Mexico's attorney general's office said in a statement.

The motive was not immediately known.

Moments before the shooting, the official, who was wearing shorts and a sleeveless shirt, paid his parking ticket at an automated machine, according to another video. After the official walks away, the gunman is seen following him.

READ MORE: Meet the man cleaning up after Mexico's murders

The FBI offered a $20,000 reward for information about the attacker.

The US embassy declined to give more details about the shooting or the official's title and identity.

In 2010, a consular official, her husband, and the spouse of another consular official were killed in two simultaneous attacks in the northern city of Ciudad Juarez, which at the time was considered the world's murder capital amid an ultra-violent drug war.

A year later gunmen from the Zetas drug cartel opened fire on a vehicle of two US Immigration and Customs Enforcement (ICE) agents in the northern state of San Luis Potosi, killing one of the officers.

Este es el hombre por quien se ofrecen 20 mil dólares de recompensa por disparar contra oficial en @USCGGuadalajara pic.twitter.com/3XxvvDiE8F — Embajada EU en Mex (@USEmbassyMEX) January 7, 2017

In 2012 two US officials, widely reported to be CIA agents, and a Mexican marine were wounded when they were shot at by federal police officers as they were driving in the central state of Morelos.

Fourteen officers were initially accused of attempted murder, but they were later put on trial on charges of using excessive force, with officials saying it was a case of mistaken identity.

In a case that caused friction between the US and Mexican governments in 1985, undercover US agent Enrique "Kiki" Camarena was tortured and killed by the Guadalajara drug cartel.