chimpssmallChester Zoo in northern England was evacuated Sunday after a number of chimpanzees broke out of their island enclosure.

At the time of writing, zookeepers were still attempting to recapture the apes who were found in an area where their food is prepared. It was unclear how the chimps escaped.

None of the chimps had escaped into public areas but the zoo was closed as a precaution, the zoo said in a statement.

Chester Zoo’s 30-strong community is the largest group of breeding chimps in Europe.