A series of bombs packed with ball bearings exploded outside a provincial headquarters of China's ruling Communist Party on Wednesday, police and reports said, killing at least one person days after a fiery attack in Tiananmen Square.
The blasts in Taiyuan come a little over a week after a fatal car crash described by authorities as a "terrorist attack" at the symbolic heart of the Chinese state, and days ahead of a highly anticipated meeting of top party leaders in Beijing.
"There were several explosions caused by small explosive devices near the party provincial commission in Taiyuan," the capital of the northern province of Shanxi, local police said on a verified social media account.
Eight "explosive sounds" were heard, the official Xinhua news agency said, adding that police "discovered ball bearings and explosive devices made using electric circuitboards" at the scene.
Metal fragments such as ball bearings and nails are used in bombs to increase injuries.
The finds indicated the blasts were "self-made bombs", Xinhua cited police as saying.
One person was confirmed dead, another was severely wounded and seven slightly hurt in the blasts, a provincial government news portal said, citing police.
"Witnesses said that there were seven sounds of explosion that lasted several minutes and were very powerful," Chinese media company Caixin reported on its verified microblog.
"Some interviewees said that they could feel the power of the blast wave even 100 metres away and that the ground was shaking."
Pictures posted on China's hugely popular weibo social networks showed vehicle doors peppered with small impacts, and tyres with holes punched through them.
Other photos showed car windows blown out and debris scattered across the road, and one showed two metal spheres, the size of large marbles, that appeared to have been among the ball bearings sprayed by the bombs.
Images showed several fire engines on a road which had been blocked to traffic, and a large crowd on one side of the street.
State broadcaster CCTV reported that some of the explosives detonated in flowerbeds at the entrance to the party provincial commission.
Xinhua quoted two witnesses who said they heard a loud noise, then saw smoke, followed by a minivan exploding.
The street where the explosions happened was the scene of a protest by some 200 laid-off workers last week, according to microblog postings.
Caixin cited sources with knowledge of the matter as saying that "major leaders of Shanxi, including those in charge of petition work and public security, are holding an emergency meeting".
Authorities maintain tight control over public security in the one-party state and place huge importance on maintaining social order.
While protests happen regularly, incidents of targeted violence are normally rare.
But on Monday last week a car barrelled into Beijing's Tiananmen Square, killing two tourists and injuring dozens. The three people inside also died after they set the vehicle on fire.
Authorities termed that incident "terrorism" and have said that it was carried out by several people from China's far-western Xinjiang region, home to the mostly Muslim Uighur minority.
China's top security official said a separatist group known as the East Turkestan Islamic Movement was a behind-the-scenes supporter of the attack.
The Taiyuan explosions also come ahead of a highly anticipated meeting of top party leaders in Beijing this weekend, at which broad economic reforms are among the items expected to be on the agenda.
Following the Tiananmen attack, authorities moved quickly to clamp down on discussion of the incident, deleting photos and comments posted on China's popular online social networks.
But the Chinese Internet was abuzz with dispatches and photos of the Taiyuan explosions on Wednesday, and "Shanxi provincial commission" was the sixth-most-popular search term on China's Twitter-like Sina Weibo site Wednesday morning, with "Taiyuan explosion" at number nine.