Estonia has made the first arrests in a money laundering scandal involving Denmark's Danske Bank, detaining 10 former employees at the bank's Estonian branch, the state prosecutor said Wednesday.

Authorities in Denmark, Estonia, Britain and the United States are investigating payments totalling €200 billion made through the Danish bank's tiny Estonian branch between 2007 and 2015.

"Six people had been detained by the criminal police on Tuesday and an additional four on Wednesday morning," the Estonian prosecutor said in a statement.

"There is reason to suspect they knowingly transferred clients' money which were under money laundering suspicion," the statement said.

In a report published in September, Danske said it had reported 42 former employees and agents "deemed to have been involved in some suspicious activity" to the Estonian Financial Intelligence Unit.

The bank had also reported eight former employees to the Estonian police.

Danske could not confirm on Wednesday if the 10 detained people were among the employees already reported to Estonian authorities, a spokesman said. He had no further information about the arrests.