The Toronto Zoo is investigating how a group of visitors got a little too close to one of two giant pandas.

Reports say some children and adults got into an area deemed “off limits,” coming within centimetres of panda Da Mao, only separated by a chain link fence.

Officials are looking into how a secondary barrier door — around 4.6 metres high — was left unlocked, which allowed visitors to enter the area next to the panda enclosure that houses Da Mao.

Giant pandas Da Mao and Er Shun, who are on loan from China, arrived at the zoo in March 2013, and the exhibit opened in May.

The CBC reports the door was closed but the padlock was not it.

Tracey told the Toronto Sun that staff last saw the door closed at 5:15 p.m., but then it reopened by 5:30 p.m. The CBC reports zoo officials didn’t know about the issue until 5:42 p.m.

According to the Sun report, some people thought the space was part of the exhibit.

A cellphone video, obtained by the Sun, also reportedly shows some people sticking their fingers through the fence.

The video shows visitors taking photos, and at one point, a child leans against the fence, which appears to startle Da Mao.

Tracey told the CBC although the pandas are cuddly, they are dangerous bears.

The incident came three months after a couple of high school students got in trouble for hopping a fence, so they could get closer to Humphrey, one of the zoo’s polar bears, to take a selfie.