File photo: AP

ISTANBUL, Dec. 19 (Xinhua) -- A total of 81 horses were killed in Istanbul following an outbreak of glanders, local authorities announced Thursday.

The plague was identified on Princes' Islands, an archipelago off Istanbul in the Marmara Sea, during a health check of horses, donkeys and mules, the district governorship said in a written statement.

"Since there is no treatment and vaccination against glanders, the animals that have been diagnosed with it should be exterminated under the relevant legislation," said the statement.

The authorities also imposed quarantine and banned animal entry and exit from the islands.

The horses were used for phaetons on the islands, which are among popular tourist attractions in Istanbul.