A submarine which is believed to have been designed to smuggle cocaine to Mexico has been seized in Colombia.

The Colombian navy discovered the 31m-long (100ft) vessel which officials said was capable of travelling 9m (30ft) below water.

On board was sophisticated navigational equipment, which would have allowed the crew to sail as far as Mexico.

The officials said it could carry four people and up to eight tonnes of cargo - they estimated it would have cost about $2m to build.