The front entrance of the Chinese consulate general in San Francisco was set on fire in an attack on Wednesday night. Chen Gang / China News Service

Police in San Francisco are investigating a possible arson attack on the Chinese consulate general on New Year's Day.

The consulate general described the case as "malicious destruction" and strongly condemned what it called a "despicable act".

A picture posted on Twitter showed the fire in front of the entrance to the building, reaching the windows of the third floor.

Police have cordoned off the site.

Pictures from the China News Service show the fire charred one of two stone lions at the entrance, turning the door black, but the rest of the building appeared unaffected.

No casualties have been reported so far.

"We urge the US to take all necessary measures to provide adequate protection for Chinese consular personnel and properties, and bring the culprits to justice as soon as possible," the Chinese consulate said on its website.

Surveillance cameras inside the consulate showed a person getting out of a minivan in front of the building, splashing the front gate with two buckets of gasoline and then setting it on fire at 9:25 pm on Wednesday.

The fire was reported at 9:33 pm, and was brought under control at 9:42 pm, a fire dispatcher told ABC7 News.

"The case is still under investigation by police in the United States. Through the surveillance camera in our complex, we saw one person get out of the vehicle. As to the specific number of suspects and the cause of the blaze, we will wait for the results of the local police investigation," said Wang Chuan, spokesman for the Chinese consulate general.

The consulate's statement said the arson attack was a violent crime targeting the Chinese consulate, adding that it caused severe damage to the consular facilities and posed a threat to the safety of staff as well as the neighborhood.