Berlin's zoo has closed its doors without warning out of precaution after a case of avian flu was discovered in a wading bird that died earlier this week, it has said in a statement.
The zoo, which welcomed over 3.7 million guests in 2019, its latest figure, did not mention when it would reopen to visitors.
"We have reacted immediately with far-reaching quarantine measures. Almost all birds - including our penguins - have now been moved to rear aviaries or stables," Christian Kern, the zoological director of the zoo in Berlin's centre as well as the Tierpark zoo in the eastern part of the German capital, said.
Kern added that no other birds were showing corresponding signs of illness but all would still be tested for bird flu.
The entire zoo has been closed to visitors to avoid the risk of bird flu being introduced into other populations, according to the statement, and staff are wearing protective clothing.
The spread of highly pathogenic avian influenza (HPAI), commonly called bird flu, is a concern for governments and the poultry industry due to the devastation it can cause to flocks, the possibility of trade restrictions and a risk of human transmission.