A man jumped into the Berlin zoo enclosure of famed polar bear Knut this morning, police say, but officials were able to keep him away from the animal.

The 30-year-old jumped over a fence into a water-filled ditch at the edge of the enclosure. Zoo officials managed to distract two-year-old Knut and lured him into his cage.

Officers later led the man away unharmed. Police said the intruder told them that he felt lonely and that Knut also appeared to be lonely. The man did not give the impression of being mentally disturbed, police said.

Knut was hand-reared after his mother rejected him at birth. He rose to fame early last year as a cute little white ball of fluff, but has since grown rapidly into a 440lb (200kg) predator.

Zookeepers have become increasingly worried about the bear's psychological health – the rejection by his mother and human hand-rearing have left him addicted to human laughter and applause.

One keeper said Knut had become so used to attention that he cried when no one was near his enclosure.

Thomas Dorflein, the keeper who reared Knut, was found dead in his Berlin flat in September.