Eight people were arrested on Friday, for smuggling electronic products from Hong Kong to Shenzhen via a 600-m-long tunnel, border police here said yesterday.

A joint operation carried out by police and customs officials from the two cities also led to the seizure of a range of goods, including computer memory chips, CPUs, motherboards and mobile phones, valued at 8 million yuan ($1.2 million), Shenzhen frontier police said.

Since the launch in January of a campaign against smuggling, authorities on the two sides have seized more than 20 million yuan worth of products, police said.

The latest case began with a tip-off received on Friday morning from a resident of Shenzhen's Luohu district.

Following the lead, frontier police were sent to a waste-processing site where they found the entrance to a tunnel hidden beneath a cargo container. Four men were arrested at the site, and about 3,800 computer memory chips and more than 3,000 new and used mobile phones were seized, police said.

The items had been smuggled across the border through a 12-cm-diameter tunnel, using an electric motor attached to a length of heavy-duty rope, they said.

In a simultaneous raid, frontier police and customs officers arrested four men at a shed used to conceal the Hong Kong end of the tunnel. They also seized electronic products valued at more than HK$7 million ($900,000).

Following efforts by authorities in Shenzhen and Hong Kong to combat smuggling, criminals are becoming increasingly inventive in their approaches, a Shenzhen customs official said.

In May, a joint police operation led to the arrest of 16 people for smuggling electronic products across the border using a fishing line strung between two buildings.