The lions, 14-year-old Sultan and 11-year-old Elsa, entered the open-air area occupied by the 17-year-old tiger Isabella by opening a trap door, Liberec Zoo spokesman Ivan Langr said. He said it happened too quickly for authorities to prevent the attack and subsequent death of Isabella.

The lions and tigers share the same pavilion overnight, which they leave for separate open-air areas during the day. The animals are allowed to enter various areas on a rotating daily basis and the lions were probably trying to enter the enclosure where they had spent the previous day, Mr Langr said.

He said the zoo will now abandon the rotating system, which has been in place since the pavilion was built in 1994.

The Liberec Zoo is the only zoo in the Czech Republic that has white tigers.

Isabella arrived as a 2-year-old in 1994, together with her brother, Columbus, from the Eskilstuna Zoo in Sweden. They were the first white tigers in Liberec. In 2002, she gave birth to triplets, Paris, Surya Bara and Artemis.

The local ice hockey team, which plays in the top Czech league is called "The White Tigers."

"She was an icon for us," Mr Langr said.

White tigers are the result of both parents having a recessive gene for white coloration. They are rare in the wild because they stand out in the jungle, hindering their efforts to catch prey.

The zoo, established in 1919, is the oldest in the Czech Republic. It has about 1,000 animals.