Investigators walk in the building where the blast occurred in Furong District of Changsha, capital of central China's Hunan Province, July 30, 2010. An explosion went off on the third floor of a branch of Furong District's taxation office on Hengda Road near a downtown residential block at about 4:15 p.m. on Friday, causing at least two people dead and more than ten others injured. The police were investigating the cause of the explosion. Photo: Xinhua

Death toll from a Friday explosion in Changsha City, capital of central China's Hunan Province, has risen to four with 19 people injured, local police said.

The explosion went off on the third floor of a branch of Furong District's taxation office on Hengda Road near a downtown residential block at about 4:15 p.m., according to a statement from the city's police.

Initial investigations show the explosion was a planned attack, the police said.

The police sealed off the building and blocked nearby roads for investigation. All the workers in the building had already evacuated before the police came.

Windows of the third floor were all shattered. Large blood stains could been seen on the stairs.

The injured have been sent to the hospital.

In a separate case in northeast China's Jilin Province, one people was killed and 20 were injured Friday in a series of explosions in a barber's shop in provincial capital Changchun.

Four fire fighters were among the injured of the explosions which first blasted at 4:46 p.m, according to a statement from the municipal government.

Witnesses say four explosions hit the shop.

Fire fighters and workers from a local gas supply company are working at the site. Pieces of shattered windows can be seen forty meters away.

The police are investigating the cause of the explosion.

A policeman guards at the blast site in Furong District of Changsha, capital of central China's Hunan Province, July 30, 2010. An explosion went off on the third floor of a branch of Furong District's taxation office on Hengda Road near a downtown residential block at about 4:15 p.m. on Friday, causing at least two people dead and more than ten others injured. The police were investigating the cause of the explosion. Photo: Xinhua

Workers clean up the blast site in Furong District of Changsha, capital of central China's Hunan Province, July 30, 2010. An explosion went off on the third floor of a branch of Furong District's taxation office on Hengda Road near a downtown residential block at about 4:15 p.m. on Friday, causing at least two people dead and more than ten others injured. The cause of the explosion was still under investigation. The police were investigating the cause of the explosion. Photo: Xinhua