GABORONE (Reuters) - A high-tech Zeppelin that mining giant De Beers was using to explore for diamonds in Botswana crashed on Thursday, state media reported.

There were no immediate reports of injuries as a result of the crash, which occurred in the central part of the southern African nation, state television said, citing a police official.

De Beers, which is 45 percent owned by Anglo American Plc and controls around half of the world's diamond supply, was using the leased Zeppelin to peer beneath the sands of Botswana's Kalahari desert for overlooked diamond deposits.

Botswana's most obvious deposits, where gems were thrust close to the surface, have already been uncovered and De Beers' joint venture with the government -- Debswana -- has been under heavy pressure to find new sources.

Botswana is the world's biggest diamond producer by value. De Beers has been prospecting there for about 50 years.