After 43 monkeys escaped a research facility in a small South Carolina town, police on Thursday urged residents to lock their homes and avoid approaching the animals under any circumstances.

In a statement posted on its Facebook page, the Yemassee, South Carolina, police department said the young female rhesus macaques escaped Wednesday. 

Police in the town of about 2,000 were helping employees of the research center, Alpha Genesis, search for the escapees.

Search teams were “working to entice them with food,” the police department said on social media.

“Residents are urged to keep their doors and windows securely closed and to report any sighting immediately by dialing 911. Please do not attempt to approach these animals under any circumstances,” it said.

The police did not say how the monkeys escaped their enclosures. Alpha Genesis, which specialises in primate-based biomedical research, did not respond to an email from Reuters or return a call.

The police said they had been informed by Alpha Genesis that the monkeys have never been used for testing and are too young to carry disease. 

Greg Westergaard, CEO of Alpha Genesis, said the escape was “frustrating,” telling CBS News he is “hoping for a happy ending” with the primates returning of their own volition.

He said that the primates were able to roam free after a caretaker failed to secure a door at an enclosure.

“It’s really like follow-the-leader. You see one go and the others go,” Westergaard said.