A fresh explosion rocked a southern Chinese town early today damaging a six-storey building, a day after parcel bombs triggered 17 explosions killing seven people and injuring over 50.



The blast took place about 8 am (local time) in Liucheng county in China's southwestern Guangxi province as the country celebrated its National Day.



The explosion occurred in a civilian's house near the local highway administration bureau in Liucheng, state-run Xinhua news agency said stating that no casualties were reported.



The explosion caused damage to a six-storey building, with bricks scattered around, the report said.



While officials said it was not a terrorist attack, the state-agency reported that police have arrested a 33-year-old, surnamed Wei who hails from from Dapu township in Guangxi.



Wei hired others to help deliver letter bombs, police said without assigning reasons for his violent actions.



Liuzhou authorities have tightened supervision over delivery packages, with the local branch of state-owned mail delivery company China Post halting all its mail deliveries until Saturday.



Police warned the public not to accept materials delivered by strangers, nor should they accept parcels received via unofficial channels.



Initial investigations suggest that yesterday's explosions were caused by 17 package bombs, with blasts reported in more than a dozen locations, including government offices, a prison, a train station, a hospital and a shopping centre.



Seven people were killed and 51 injured. Photos posted on social media showed portions of multi-storey buildings gutted and collapsed, and streets littered with glass, bricks and other debris.



Surveillance video footage of one explosion showed a person catapulted out when bomb went off in a market store.



The blasts apparently were triggered by devices placed inside express delivery packages, Xinhua reported.



The timing of the explosions were intriguing as they took place ahead of China's National Day today which also marks the 60th anniversary of integration of the volatile Xinjiang province in China as an autonomous province.



All Chinese cities are under thick blanket of security this year following a number of sword attacks by the militants East Turkistan Islamic Movement, (ETIM) which has become active in Xinjiang where native Uyghur Muslims were restive over the settlements of Han Chinese in recent years.



Senior leader of the ruling Communist Party of China, (CPC) Yu Zhengsheng who visited Xinjiang today said that long-term stability and security was the top priority of the province.



Yu, chairman of the National Committee of the Chinese People's Political Consultative Conference said "we must be fully aware of the severe situation we are facing to maintain long-term stability in Xinjiang."



"Counter terrorism is the focus of our current work," he said.



The government will also address other social problems, he said, adding that it will balance security efforts with the need for economic development, Xinhua reported.



Yesterday's explosions took place in at least 13 locations in rural Liucheng, including a business trade mall, a prison, a government building in Dapu township, a supermarket, a bus station and a hospital.



While the local government said the initial investigation indicates this is a criminal case, Dai Peng, director of the Criminal Investigation College at the People's Public Security University of China, said it might be too early to make such a conclusion, state-run China Daily reported.



The blasts might have exposed "loopholes of management of the express delivery industry", Dai said.



He said the blasts might point to the need for real-name registration of both package senders and receivers.