Police hunted Monday for chimpanzees that escaped from a Sierra Leone preserve and mauled a group of local and American sightseers — a rare attack that left one local man dead and at least four other people hospitalized.

The U.S. Embassy warned Americans against traveling to the Tacugama Chimpanzee Sanctuary, from where the chimps escaped before the Sunday attack on a taxicab filled with Americans and others.

The Sierra Leonean driver died as the chimps ripped his body apart and the three Americans were treated at a local hospital for minor injuries, said a top police official, Oliver Somasa.

Another Sierra Leonean man in the group had his hand amputated after the primate mauling, Somasa said. U.S. officials had no further comment. The Americans were in Sierra Leone to help construct a new embassy building, Somasa said.

Armed police were searching Monday for 27 chimpanzees, Somasa said, while four other chimps had already returned on their own accord to the reserve.

Somasa said it was unclear why the chimps attacked or how the chimps were able to flee the park.

Chimpanzee attacks are unusual but not unprecedented.

Two chimps that escaped from their cages in a California sanctuary severely mauled one man last year, injuring his genitals and limbs. A bystander shot the primates before they could kill their victim.