This story has been updated.

Update, 9:52 a.m. EDT: At least 12 people have been killed in Tbilisi, Georgia, after a number of zoo animals, including lions, tigers and a hippopotamus escaped from the city's zoo. Of the 12 dead, three are zoo workers, the Associated Press reported Sunday morning. Authorities have warned residents to stay inside.

Original story appears below.

At least 8 people have been killed, and a number of zoo animals have escaped their confinement in the Georgian capital Tbilisi, after heavy flooding struck the city.

One zoo keeper was believed to have been killed in the flooding, along with a number of animals from the city's zoo. The city's mayor, Davit Narmania said the situation was "very grave", according to a BBC report.

Agency photos showed a hippopotamus in one of the city's main squares, being targeted by an officer with a tranquilizer gun.

In addition to the hippo, reports suggest that six tigers, six lions and eight bears broke free of their enclosures, and took to the city's streets.

Of the zoo's 600 residents, including fish and birds, about half are missing, Tbilisi Zoo said. Some animals have been re-captured and others killed, according to a report from the news agency,, cited by CNN.

Heavy rainfall turned the Vere river flowing through the capital of the former Soviet republic into a torrent that swept away dozens of buildings and cars, the Guardian reported.