An explosion damaged a six-story building Thursday in southern China, less than a day after more than a dozen blasts triggered by explosive devices delivered in mail packages killed at least seven people and injured over 50 in the same small city in southern China, officials and state media said.

The latest blast hit a civilian's house near a highway administration bureau in Liucheng, but it was not immediately known if there were any casualties, according to the official Xinhua News Agency.

The Ministry of Public Security said it was treating the blasts on Wednesday as a criminal act, and not terrorism. It said a 33-year-old local man, identified only by his family name of Wei, was considered a suspect, but provided no further details, including a possible motive or whether the man had been detained. Local media reported that the suspect had been apprehended.

A local Communist Party newspaper, the Guangxi Daily, cited police as saying there were 17 explosions Wednesday afternoon in Liucheng, leaving seven people dead, two missing and 51 injured.

Police in Liucheng said they will hold a news conference later Thursday.

Wednesday's explosions, which occurred between 3:15 p.m. and 5 p.m., hit a hospital, local markets, a shopping mall, a bus station and several government buildings, including a jail and dormitories for government workers, according to a police statement posted by the local newspaper Nanguo Zaobao.

"There were so many of them, and they were so loud, everyone in (Liucheng) could hear them," said a hotel employee who gave only his family name, Li. The hotel is near a township office building that was hit by one of the explosions.

"They sounded like someone was blasting rocks in the mountains," Li said.

Zhou Changqing, the police chief for the city of Liuzhou, which has jurisdiction over Liucheng, said the blasts were triggered by explosive devices delivered in several mail packages, state broadcaster CCTV reported.

A supermarket employee said the store was evacuated immediately when an adjacent supermarket was hit by an explosion.

"All of us heard the blast. It was very loud," he said by phone.

Photos posted online showed streets filled with smoke, strewn debris, dust clouds in the sky and the rubble from a five-story building that had partially collapsed.

The official Xinhua News Agency reported that at least one more explosion hit downtown Liuzhou, away from Liucheng. It did not say whether there were any casualties from that blast or whether it was connected to the ones in Liucheng.