A new explosion has hit Guangxi province, a day after a series of parcel bombs killed seven people, Chinese authorities say.

The blast took place at an apartment block at 08:00 local time in Liucheng county, said state media.

The cause was not clear, and no casualties have been reported.

Seventeen separate explosions hit Liucheng on September 30. Police have arrested a suspect they believe sent out the bombs in the mail.

It is unclear whether today’s blast is connected to the multiple blasts on the previous day.

The new explosion took place at a six-storey building in a residential area. Xinhua news agency said the force of the blast had caused debris to rain down on a road opposite the building.

Local police issued a statement calling on the public to be wary of accepting parcels sent by strangers or packages “sent by non-proper channels”.

The local postal service has halted all deliveries until October 3.

The parcel bombs on September 30 targeted a prison, a train station, a hospital and a shopping centre among other locations.

State media said besides the seven dead, another two people remained missing and 51 people were injured in afternoon’s blasts.

A 33-year-old Liucheng resident, identified only by the surname Wei, is in police custody for the explosions.

There have been a number of cases in China of disaffected people with a legal grievance against the authorities using explosive devices in public attacks.