A suspect has been detained in connection with Sunday's deadly explosion in Ningbo, Zhejiang province, according to the social media account of the Ningbo police on Tuesday.

The authorities said that the careless disposal of explosive substances could have led to the explosion.

According to the authorities, the explosion centered on a septic tank near which a truck loaded with illegally manufactured explosives was parked.

The explosives－including aluminum powder and barium nitrate－were transported to Ningbo from Liaoning province. The truck had been parked at the site since 3 pm on Saturday. The materials, which belonged to a man surnamed Shan, originated in Fuyang city of neighboring Anhui province.

In Liaoning, the Tieling police issued an online arrest warrant for Shan on Oct 25. He was suspected of illegally manufacturing and trading the materials.

Shan was traced and then detained by the police at 9 pm on Monday in Panqiao village of Huangshi, Hubei province, where he was hiding.

The police said the 33-year-old suspect acknowledged transporting the explosives to Ningbo to avoid being discovered by the police in Liaoning.

According to the police, Shan asked relatives in Ningbo to drive a truck loaded with the hazardous materials and park it at a disposal site. Evidence at the site indicated that some of the explosives were dismantled and destroyed on Saturday night. At around 8:40 am Sunday, the disposal operation resumed, the police said.

About 15 minutes later, the deadly explosion occurred. Two people died and dozens were injured. Two people remain missing.

The police ruled out the possibility that the deadly explosion had been planned. The blast smashed nearby cars and severely damaged surrounding buildings, affecting hundreds of residents.