An animal keeper at the Calgary Zoo has been injured after an incident with a gorilla.

The employee was in the kitchen in the rainforest exhibit around 9:15 a.m. MT Friday when he turned around to find a gorilla.

Officials say the gorilla was contained but the keeper did receive a minor injury. The worker is recovering after being released from hospital.

A keeper received a minor injury after gorillas entered the kitchen in the exhibit, which normally is for humans only. (CBC)

An emergency response team locked down the exhibit for roughly 15 minutes as it checked on the whereabouts of the six gorillas who live there.

Zoo curator Malu Celli says the public was never at harm and this is the first time an incident like this has happened since the exhibit opened in 2003.

"It is an unfortunate event and we'll take every step to make sure that it never happens again," said Celli. "But the positive side ... is that we know everything we put in place in case of an unfortunate situation lived up to expectations."

Zoo officials say they don't know how a gorilla got into the kitchen, as there are "gorilla-proof" locks on doors leading to the area.

The investigation will check if the zookeeper accidentally left the doors open or if the gorilla somehow figured out how to unlock them.

Officials are also looking into how many gorillas escaped the enclosure.

Another incident in 2009

Calgary Zoo gorillas also made headlines in 2009 when photos taken by a visitor surfaced of a female Western Lowland gorilla holding a knife menacingly toward a troop mate.

Zoo officials said the knife had been left in the enclosure by mistake and none of the animals were hurt.

"They're not an aggressive species at all. In fact, they're quite gentle, passive, shy, animals and most of the behavior that you see that might be seen [as aggressive] is all show and very little action," said zoo spokesperson Cathy Gaviller at the time.

A Calgary Zoo visitor snapped this photo in 2009 of gorilla Barika holding a knife accidentally left by a zookeeper. (Courtesy of Heike Scheffler)