White tigers are rare in the wild because they stand out in the jungle
Two lions at a zoo in the northern Czech Republic have killed a rare white tigress after entering her enclosure.
The incident happened at Liberec Zoo - the only one in the country which has white tigers.
Zoo workers were alerted by the cries of the tigress, but were unable to stop the killing.
White tigers - the result of a recessive gene - find it difficult to catch prey in the wild because their colouration stands out in the jungle.
The lions - Sultan, aged 14, and Elsa, 11 - managed to open a trap door leading to an open-air area occupied by the 17-year-old tigress, Isabella.
Lions and tigers in the zoo share the same pavilion overnight, which they leave for separate open-air enclosures during the day.
But the open-air enclosures are rotated, and zoo authorities believe the lions were trying to get into the area where they had spent the previous day.
"The current security system has been in place for 12 years and such an accident has never happened before," said zoo director David Nejedlo.
There are three surviving white tigers at the zoo, including Isabella's daughter.
The zoo is the oldest in the Czech Republic and was established in 1919.