Shenzhen local police have arrested three men on suspicion of blackmailing supermarkets with self-made bombs, 12 hours after an explosion in a store in the southern city on Monday.

Nobody was hurt when one of the bombs exploded in a storage cabinet of the newly-opened outlet of Carrefour, the French retailing giant, in Luohu District on Monday afternoon.

After an emergency broadcast in the supermarket, nearly 1,000 consumers and employees were evacuated to safety in minutes, according to a report by Southern Metropolis News.

The local police said that they had received bomb threats from three supermarkets shortly before the explosion, including the Carrefour outlet.

The blackmailers said they had placed bombs in the supermarkets and demanded each of them put 23,500 yuan (US$2,900) into a designated bank account.

At the Carrefour outlet, experts found that the blackmailers ignited powder in a small bottle with flaming mosquito-repellent incense.

To discover the identity of the blackmailers, the police deposited a total of 15,000 yuan (US$1,850) into the bank account, and were then able to track down the location of one of the men when he withdrew money.

The man, 23, was arrested in an Internet bar late on Monday. He quickly confessed and gave the identity of his two accomplices,who were arrested yesterday.

Editor: Yan