A 26-year-old Chinese man set off a small explosive outside the US embassy in Beijing on Thursday, sending smoke into the air and injuring his hand, before security officials rushed to the scene and took him into custody, police said.
Chinese police said no one else was injured in the incident, which took place near the area where visa applicants typically line up to enter the embassy for interviews.
The explosion was set off by a man surnamed Jiang from China's Inner Mongolia region, police said. His injuries were not life-threatening. Police did not indicate a possible motive.
Video clips that circulated on social media shortly after the explosion showed smoke in the air outside the embassy compound, and AFP journalists arriving at the scene found heavy Chinese security.
"We heard a rather strong explosion around 1.00pm local time [9.00am UAE time], so we went out on the street to have a look, but very soon the police had cordoned off the area," said a witness who declined to be identified.
Police quickly cordoned off the spot where the blast took place, and China's state-censorship apparatus moved swiftly to block searches for "US Embassy" on popular Twitter-like platform Weibo.
AFP journalists said the visa office adjacent to where the blast took place appeared to have resumed operations not long after the incident.
"I heard a loud 'bang', and then we all craned our heads to see what it was," said a man surnamed Liu, who was waiting outside the embassy at the time.
"It seemed [police] reacted pretty quickly, like they were prepared."
The area where the incident took place is on the outskirts of Beijing and home to several embassies, including those of India and Israel.
China regularly sees cases of disgruntled individuals lashing out at society over various grievances or perceived injustices, often harming themselves or others.
In one of the worst recent incidents, a bomb blast killed eight people and injured dozens of others outside a kindergarten in eastern China in June of last year.
Police blamed it on a 22-year-old man who was suffering from health problems.
The state-run Global Times reported separately, citing witnesses, that police took away a woman who sprayed herself with gasoline in a suspected self-immolation attempt outside the embassy at around 11 a.m. It was not clear whether this woman's actions were related to the later explosion, the paper said.
A witness who did not want to be identified told Reuters that he saw a middle-aged woman with two buckets of gasoline. On her back were the Chinese characters for "sue them".
Beijing police and the U.S. embassy did not immediately reply to a request for comment on the woman.