The operation will impact as much as 15,000 workers, but there will be no job cuts, the source said.

As part of the operation weekly working hours of thousands of people will be cut by 2 hours from 2019.

Deutsche Telekom, which according to the source will issue a statement later on Thursday, was not immediately available to comment.

(Reporting by Harro ten Wolde; Editing by Andreas Framke)