A spokesman for the consulate said surveillance footage showed a person coming out of a van parked outside the compound with two buckets, pouring the contents on the front of the building and setting it on fire.

The consulate has a surveillance camera outside the building located in San Francisco's Western Addition district.

Spokesman Wang Chuan said: "We strongly condemn this despicable act and have already made representation with the U.S. on the attack. And we hope that the U.S. takes all necessary measures to provide adequate protection to the consular personnel and properties and bring the culprits to justice as soon as possible."

The consulate is awaiting results from the investigation and will not speculate on who is behind the attack, he said. He said they don't yet know how much repairs will cost.

Lee said he did not know whether the consulate had received any threats recently or any demonstrations at the site. Police stepped up their presence in the area around the consulate building on Thursday.

The U.S. State Department was in immediate contact with Chinese consulate and embassy in Washington after Wednesday's fire in San Francisco, department spokeswoman Marie Harf said Thursday from Washington.

Harf said it was too early to judge whether security at the consulate had been adequate.

"We take this incident very seriously, and the Bureau of Diplomatic Security is working with the FBI and local authorities to investigate and apprehend the perpetrators," Harf said. "Department officials are communicating with Chinese officials to provide support and updates on the case."

San Francisco police and firefighters arrived at the scene of the fire at the Chinese Consulate around 9:30 p.m. Wednesday and crews brought the flames under control within minutes, fire department spokeswoman Mindy Talmadge said.

The fire caused "serious damage to the facilities of the consulate and endangered the safety of the consulate officials and the citizens living nearby,'' Chuan said.

California Assembly Speaker John Perez said in a statement Thursday condemned the incident.

"This kind of shameful attack has no place in California. While we are fortunate there was no injury or major damage, this attack on one of our diplomatic partners must be condemned,'' Perez said. "I am confident the FBI and all law enforcement agencies involved will pursue a vigorous investigation and bring the perpetrators to justice.''

Chinese Consulate fireChinese Consulate fire

In San Francisco, Chinese Consulate Says Arsonist Caused Blaze