Concerns are growing over a lack of safety measures at public zoos after a keeper was seriously attacked by a Siberian tiger.

A 3-year-old tiger bit the keeper’s neck at its temporary compound at Seoul Grand Park in Gwacheon, Gyeonggi Province on Sunday morning. The 52-year-old keeper was moved to a nearby hospital, but is still in a coma.

The Seoul City government on Monday officially apologized for causing concern and said it would strengthen safety measures at the park. The Seoul city government is the operator of the public park. Planned improvements include fortifying big cat enclosures, installing surveillance cameras and building higher fences ― raising them from the current 1.5 meters to 5 meters.

In its internal report, the city government said that the keeper was laying food inside the tiger compound but was not aware that the door which was supposed to lock the tiger inside had been left open and that the animal had walked out from its enclosure.

Officials said they were investigating how the big cat attempted to escape the compound and how the door inside was left unlocked. But they are having trouble because the compound didn’t have any surveillance cameras to track the animal’s movement.

“We are having difficulties with finding the cause because the case has no witness or surveillance camera,” an official said.

The city government said it will look into whether the zoo has had a protocol for installing surveillance cameras inside the animal compound.

The Siberian tiger named Rostov was placed in a compound that used to house foxes in April. Some officials said the compound may have been too small for him.

By Cho Chung-un (christory@heraldcorp.com)