Heavy flooding in the Georgian capital, Tbilisi, has killed at least 12 people, with officials warning people to stay indoors to avoid animals that have escaped from a zoo.

The missing animals include tigers, lions, bears and wolves. Three of the dead people were found within the zoo.

A hippopotamus was cornered in one of the city's main squares and subdued with a tranquiliser gun.

Officials said the flooding in the Georgian capital was the worst natural disaster in recent memory.

Among the dead was one zoo worker, Guliko Chitadze, who had an arm amputated two weeks ago after a tiger mauled it. She had returned to work just a few days ago. Her husband, also a zoo worker, was also killed, zoo spokeswoman Mzia Sharashidze said. The workers had spent the night on zoo premises to feed newborn animals.