The explosions went off in the city of Fuzhou at roughly 10-minute intervals shortly after 9:00 am (0100 GMT), an official with the provincial propaganda department told AFP.

The first was a car explosion in the parking garage of the city prosecutor's office, the second occurred on the first floor of a district government office, and the last was a car blast next to the city's food and drug agency, said Zhang, who declined to give his full name.

He said authorities were investigating the causes of the explosions and had no immediate information on casualties.

However, the official Xinhua news agency quoted witnesses saying at least five people were injured.

The incident is likely to add to official fears over possible public unrest stemming from a range of grievances, with soaring inflation topping the list.

China sees thousands of protests and other public disturbances each year, often linked to anger over official corruption, government abuses and the illegal seizure of land for development. But bomb attacks are extremely rare.

At least 10 vehicles were damaged in the explosions, which also shattered windows in the buildings, Xinhua said.

The news agency added that the prosecutors' office and the Linchuan district government office are located just minutes apart.

Pictures posted on the Twitter-like microblog account of the official China News Service showed a white plume of smoke towering over crowds of onlookers.

More than 40 people were injured earlier this month when a disgruntled former employee set off a petrol bomb at a bank in a Tibetan-inhabited region of northwest China, according to authorities.

Copyright APP (Associated Press of Pakistan), 2011

Copyright AFP (Agence France-Presse), 2011