Montenegro Airlines' co-pilots have been accused of staging a silent protest, forcing the cancellation and delay of a number of flights last week. Montenegro Airlines says the co-pilots are not on an official strike but have failed to turn up to work for "reasons unknown". "The management has not been informed on behalf of airline operations of any strike. A strike entails a timely announcement and for minimum working conditions to be secured", the carrier said. During last week, Air Serbia operated some flights on behalf of Montenegro Airlines. Over the past few days the airline has been cancelling, rescheduling, delaying and linking up a number of its services. Its flight from Podgorica to Ljubljana was cancelled yesterday for "operational reasons". Most of the company's co-pilots are believed to be staging a silent protest over unpaid wages and have called in sick. Last Wednesday, only one of seventeen co-pilots showed up to work. The carrier has been threatened with industrial action over unpaid wages on a number of occasions over the past year. Montenegro Airlines is to select a new management team on January 27, following the surprise resignation of the head of the Board of Directors.