Police named a 33-year-old man from Liucheng Tai Po town as a suspect in the explosions and said their investigations were continuing, Xinhua reported.
The People's Daily, a national newspaper, said the suspect paid couriers to deliver the letter bombs across Liucheng. A further 60 suspicious parcels had been identified and bomb disposal were "on their way."
On Thursday, Xinhua reported another explosion at a residential building at around 8 am. There were no initial reports of casualties.