BEIJING — A 26-year-old man was detained by police Thursday after detonating a small explosive device outside the U.S. Embassy in China’s capital.

He was the only person injured in the blast, which sent a cloud of smoke into the air at about 1 p.m. local time (midnight ET).

The Beijing Public Security Bureau said the suspect was taken to hospital and placed under investigation. There was no word on a motive.

“A man detonated what is suspected as firecracker-like explosive device,” the agency said via China's Twitter-like Weibo platform. “His hand was injured but there is no life-threatening danger.”

A few plainclothes policemen are trying to scrub off marks on a sidewalk next to the American Embassy in Beijing. Pedestrians are asked to turn back. “Don’t take photos; otherwise you’ll be detained,” a policeman blocking the road said. pic.twitter.com/1d6GsaeQcE — Xinyan (@xinyanyu) July 26, 2018

The suspect's family name is Jiang and he is from the city of Tongliao in Inner Mongolia, which is about 450 miles northeast of Beijing, according to officials.

Aside from a heightened security presence and some broken glass, the scene returned to normal soon after the blast.

It happened in a public area near the southeast corner of the diplomatic compound, according to a U.S. Embassy statement. “Other than the bomber, there were no injuries,” it added.

Neither the police nor American officials had any comment on a report by the ruling Communist Party's Global Times newspaper that said a woman earlier Thursday sprayed gasoline on herself in a "suspected attempt at self-immolation" near the U.S. Embassy.

Alastair Jamieson reported from London. Eric Baculinao and Ed Flanagan reported from Beijing.