German authorities are looking for what they believe is a wild lioness that was reportedly seen in the south-western edges of Berlin.

Authorities were first made aware of the animal's presence after a few people - including a police office - saw it pursuing a boar.

On Wednesday, a video on Twitter which police believe is real appeared to show a lioness in a forest in Kleinmachnow.

Residents are being told to remain inside until the animal is found.

If it is a lioness, it is unclear where it came from. Local zoos, animal sanctuaries and circuses have said no lions have escaped from their facilities.

"We don't know where it came from," a police spokesperson told local media.

Brandenburg police told residents in Kleinmachnow, Teltow and Stahnsdorf to stay indoors in the early hours of Thursday morning due to the threat of an "escaped wild animal", but later tweeted: "The wild animal could be a lioness. The warning area has now been extended to the south of Berlin."

Police spokesperson Daniel Keip told public broadcaster RBB that "in the summer you often hear reports of crocodiles in swimming lakes and then it turns out all it was, was a big duck. In this case it's obviously totally real. We're dealing with a lioness that's roaming freely through Teltow, Stahnsdorf and Kleinmachnow."

But Michel Rogall, a circus director in Teltow who was woken by police at 02:00 local time is not so sure.

"If it's a lion, I'll eat my broom," he told the Tagesspiegel newspaper.

As well as themselves, residents have been advised to keep their pets indoors. Police have also told people to avoid the forest, and seek shelter immediately if they see the lion.

Helicopters have been deployed to try and find the elusive animal, authorities said.

Veterinarians and hunters with tranquiliser guns are also involved in the search. Bild said authorities are hoping to capture it in a humane way.

Authorities currently believe it may be sleeping in a wooded area, it added.

Florian Eiserlo of the Four Paws animal welfare organisation told the Rheinische Post newspaper that if anyone runs into the animal, they should not panic.

"Stand still, stay calm, try to head to a safe area such as a car or a building," they said.

They had better find it fast before it gets out of hand.

It is well