The US consulate in Guadalajara posted a video on Facebook Saturday showing the shooter, dressed in blue and wearing a wig, waiting outside a shopping center's garage at 6:20 pm on Friday (00:20 GMT Saturday). He then raises his gun and fires at the car before fleeing.
The shooting left a bullet impact on the car window while the US consular official is seen opening his door.
Moments before the shooting video from different cameras showed the official, dressed in shorts and a sleeveless shirt, paying his parking ticket at an automated machine. The gunman is seen following him.
"According to the four videos, it was a direct attack," Jalisco state attorney general Eduard Almaguer Ramirez said.
The gunman was wearing a wig and a blue nurse uniform, Almaguer said.
The US official, who is in stable condition, interviews visa applicants at the consulate, Almaguer said.
A US government official told AFP on condition of anonymity that the official is a vice consul, adding that no motive for the shooting has been established.
The western city of Guadalajara has been hit by violence perpetrated by the powerful Jalisco New Generation drug cartel in recent years.
$20,000 reward
The US Federal Bureau of Investigation offered a $20,000 reward for information about the shooter. The FBI is helping with the investigation, Almaguer said.
The Mexican attorney general's office said it was in contact with the US embassy and consulate in efforts to locate the shooter.
"The safety and security of our employees overseas is among our highest priorities," the US embassy said in a statement.
"We are working closely with Mexican law enforcement in this matter," the statement added, saying it would provide more details "due to privacy considerations."
The embassy issued a security message later Saturday urging US citizens in Guadalajara to "restrict their movements outside their homes and places of work to those truly essential."
"They should also take care not to fall into predictable patterns for those movements that are essential. They should vary the times and routes of their movements."
Not the first attack
US officials have faced attacks in Mexico in the past. 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.
An alleged leader of the Barrio Azteca gang was extradited to the United States, where he was sentenced to life in prison for ordering the murder.
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.
In 2012, two US government officials -- widely reported to be CIA agents -- and a Mexican marine where wounded in 2012 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 were later put on trial on charges of using excessive force, with officials citing a case of mistaken identity.
And 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.
