Robbers nabbed a stuffed rhinoceros head from the Brussels Natural History Museum this week in the second such robbery in Belgium in less than a month, the museum said Wednesday.

"At closing time, the head of a black 'Diceros bicornis' rhinoceros exhibited in the mammals gallery was stolen by three people," the museum said in a statement issued after the Tuesday heist.

The rhino robbers fled to a waiting car with a driver, with museum guards in hot pursuit. "They got away before we could catch then," the museum added.

Located a stone's throw from the European parliament in central Brussels, the museum is popular for its celebrated dinosaur skeletons and Wednesday stepped up security while taking rare prized pieces away from the public eye.

On June 16, a robber also working with an accomplice stole a rhino head in the Liege natural history museum but was caught and the head returned to its place.

The man made off to a waiting vehicle with Dutch number-plates after tear-gassing the guards but police threw up roadblocks and brought in the pair, both Poles.

They said the plan had been for them to leave the stolen property at the foot of a statue in the Netherlands where it was to be picked up against 3,000 euros.

Rhinos are often poached for their horns, made of keratin and sold on the black market for ornamental or medicinal purposes, particularly in Asia.

The two African species and the Sumatran rhinoceros have two horns, while the Indian and Javan rhinoceros have a single horn