“It’s a very, very sad outcome but we had no choice,” said the head of the zoo in the eastern city of Leipzig, Joerg Junhold.
The one-year-old lions, named Majo and Motshegetsi, had slipped into the main grounds of the zoo at about 8:40 am (0640 GMT), before the park opened to the public.
Zoo staff implemented an emergency plan, placing the facility on lockdown so the animals could not breach the facility’s fences.
“After Majo was caught and Motshegetsi was hit with a tranquiliser dart, we were hopeful that the breakout could end without any loss of life,” Junhold said.
However the staff then determined that they had lost control of the situation and a zookeeper shot and killed Motshegetsi.
“Human safety always comes first,” Junhold said.
The two lions originally from Namibia had only arrived in Leipzig last month from Basel Zoo.
They were given several weeks to get used to their new home before being released into an enclosure where they could be seen by the public.
The escape “surprised all of us because the enclosure had been in operation for 15 years. Of course we assume that it is secure,” Junhold said.
Last March, one tiger was killed by another at Leipzig zoo when a partition separating the two was removed by accident.
An Ohio zoo faced international uproar in May when its staff killed a critically endangered gorilla as it dragged a young boy who had fallen into its enclosure.
While acknowledging the US zookeepers had few options, critics slammed the zoo saying it should have installed more barriers. The park’s managers insisted its facility met all industry standards.