WASHINGTON - The United States is "deeply concerned" by reports that the Chinese consulate-general in San Francisco was damaged in an arson attack, the State Department said Thursday.

"We take this incident very seriously," State Department spokeswoman Marie Harf said in a statement.

On Wednesday, a person got out of a mini-van parked in front of the main entrance of the Chinese consulate-general in San Francisco, California, poured two buckets of gasoline onto the front door and set it alight, severely damaging the door, according to a statement posted on the website of the consulate- general.

The State Department's Bureau of Diplomatic Security is working with the Federal Bureau of Investigation and local authorities to investigate and apprehend the perpetrators, Harf said.

State Department officials are communicating with Chinese officials to provide support and updates on the case, she added.

China on Thursday urged the United States to take "effective measures" to protect its diplomatic institutions and staff, and prevent similar incidents following the attack.

"The Chinese Foreign Ministry and embassy and consulates to the United States have lodged solemn representations to the US side, demanding they solve the case as soon as possible and severely punish the culprit," said Chinese Foreign Ministry spokesman Qin Gang.