Image caption Officials said the tunnel cost almost $500,000 to build

Chinese authorities have uncovered a tunnel from the mainland to Hong Kong, apparently built by smugglers.

The tunnel, with concrete walls and interior lighting, started under a garage near the city of Shenzhen and stretched for 40m (130ft) under a river and into reed-beds in Hong Kong.

The authorities believe gangs intended to use it to import mobile phones and other electrical goods into Hong Kong.

The semi-autonomous zone has different tariffs to the mainland.

The smugglers could make huge profits by avoiding border fees and taxes.

Image caption The tunnel was thought to be incomplete, about 20m short of its intended destination

Image caption Drilling equipment was removed from the tunnel on Tuesday

The tunnel was discovered last week in Changling village on the outskirts of Shenzhen.

Local media reported that a resident had complained about drilling noises that she assumed were part of a renovation project.

Officials described the tunnel as a professional job, estimated to have cost almost $500,000 (£300,000) to build.

It is believed the tunnel was about 20m short of its intended destination, a village on the Hong Kong side of the frontier.

The authorities destroyed the tunnel on Tuesday and a man has been arrested.