Dutch zookeepers have shot dead two male chimpanzees after they escaped from their enclosure at the DierenPark Amersfoort zoo in the central Netherlands.
Two chimpanzees, named Mike and Karibuna, were shot after they succeeded in breaking out of their enclosure and were seen acting aggressively, the zoo said in a statement.
Visitors were warned as soon as the break-out was discovered, the zoo said, adding that no visitors or staff were harmed during the incident.
"We very much regret this incident," the statement said, adding that it was a "black day" for the zoo.
Keepers had been forced to act due to the potential danger to people, it added.
"To prevent further escalation, the two male chimpanzees were shot," the zoo said, adding that sedation had not been an option.
The statement said it believed the chimpanzees had escaped due to a human error and that it would investigate further.