Prosecutors detained four executives of two cryptocurrency exchanges on charges of stealing clients' money on Saturday.

It marks the first arrest of officials of cryptocurrency bourses in South Korea.

The Seoul Southern District Court issued an arrest warrant the previous day for the four executives including the chief of "Coinnest" surnamed Kim, saying they may try to flee or destroy evidence.

Kim and the others are accused of fraud and embezzlement. They are known to have been pocketing tens of billions of won from clients' accounts by transferring the money to their own private accounts. 

Coinnest is the sixth largest cryptocurrency exchange in the country in terms of transaction volume. The other exchange whose chief is also arrested is smaller in size.