I was amazed the first time I saw video of eagles hunting Roe Deer on the other side of the Atlantic. Khazak Eagle hunters targeting wolves, simply amazing, but this is even cooler.
Apparently, eagles have been witnessed harassing bears in the past, but just recently a golden eagle was found to be actually hunting a bear's cubs. The eagle grabbed the cub as it fell behind it's mother and flew off with it into the clouds.
On further investigation, it was found that more people had witnissed similar behavior over the years.
During spring 2004 an adult female brown bear (Ursus arctos) and her 3 cubs-of-the-year were observed outside their den on a south-facing low-alpine slope in central Norway. They remained near the den for 8–10 days and were, except for one day, observed daily by Totsås and other wardens of the Norwegian Nature Inspectorate. On 25 April, as the family was moving along the edge of a steep, treeless slope and down a snowdrift, the smallest cub, at the back of the group, was attacked by a golden eagle (Aquila chrysaetos). The cub vocalized loudly as it was lifted off the ground and carried away. The eagle was still carrying the cub when it flew into cloud cover and was lost from view. Although no remains were found, it is probable that the eagle killed the cub. This paper describes the circumstances of the incident and relates it to other observations of attacks by eagles on young bears in Europe and North America.