Shenzhen: Seven men were captured while smuggling electronic products through a 20-metre-long tunnel from Hong Kong to neighbouring Shenzhen.

The tunnel dug by the smugglers from Shenzhen to the Hong Kong side. [Information Times]

The men had to crawl through a tunnel just 67 cm wide and through a sewage pipe to get the goods across the border.

It is the first time police have uncovered a smuggling case in the southern city that involved a tunnel, said Song Min, deputy director of the anti-smuggling division of Shenzhen Customs, in a press conference yesterday.

After a one-month investigation, the anti-smuggling force took action on August 25, capturing a gang leader, a truck driver, and five men working in the tunnel.

About 900 mobile phones and 120,000 electronic chips, worth roughly 1.6 million yuan (US$200,000), were seized in the raid. This involved some 270,000 yuan (US$33,750) in unpaid taxes, Song said.

Another leading suspect is still at large. Two Hong Kong residents, including the owner of the goods and a man who delivered them, were being sought.

"We have reported the case to the Hong Kong customs and police. We think the Hong Kong suspects will be punished," Song said.

According to the customs, the gang rented a single-room apartment, with an area of about 15 square metres, last month in Shatoujiao, which is just a few metres away from the border.

Shenzhen and Hong Kong are divided by a river, but they meet in Shatoujiao.

The smugglers dug down from the floor for about one metre, and then tunnelled towards the Hong Kong side. They linked up with a sewage pipe that runs across the border.

A truck parked just outside the Shenzhen apartment received the smuggled products through a side door. The whole smuggling operation would take no longer than 3 minutes.

"The suspects confessed that they spent nearly 20 days digging the tunnel and used it three times," Song told reporters.

He estimated the gang could have smuggled about 500 to 600 million yuan (US$62.5 to US$75 million) worth products a year through the tunnel if they had not been stopped.