The entrance of the Chinese Consulate in San Francisco has been set on fire in what officials there called an arson attack.
According to a statement posted on the consulate's website, an unidentified attacker came out of a van parked outside the compound on Wednesday night with two buckets of petrol.
The person then poured the fuel on the front of the consulate building and set it on fire.
The consulate urged US authorities to protect its diplomats and premises and launch an investigation into the "despicable act".
The notice said the fire had caused serious damage.
The safety of diplomatic personnel and missions is particularly sensitive in China after the US military accidentally bombed the Chinese embassy in Belgrade during air strikes against Serbia in 1999.
The attack sparked violent anti-Nato demonstrations across China and brought relations with the US close to a breaking point.
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