Over two dozen monkeys have escaped in Puerto Rico after a lock was broken on their enclosure at a primate research facility.

Police say that as many as 30 rhesus macaques monkeys were freed yesterday morning from the Caribbean Primate Research Centre in Toa Baja.

The centre, which was established in the late 1930s, operates in conjunction with the University of Puerto Rico and supplies monkeys used to study human diseases.

Authorities have launched an effort to recapture the monkeys but so far there have been no arrests.

Puerto Rico has a long history of attempting to control large numbers of wild apes that have descended from escaped research monkeys.

The monkeys have been blamed for scavenging crops and damaging natural resources on the US Caribbean island, resulting the euthanizing of hundreds of wild monkeys.

Rhesus macaques, are one of the best known species of Old World monkeys and often live close to humans. The monkeys have believed to have complex cognitive abilities and have been involved in studies for a variety of medical breakthroghs including the development of rabies, small pox, and polio vaccines.