Frankfurt - German air traffic controllers announced plans to strike at all airports in two weeks' time, the first time Germany has ever faced a formal, nationwide stoppage by control-tower staff.

The GdF aviation safety union said it would allow 25 per cent of staff to offer a skeleton service, but gave no other details.

The strike, expected to begin April 14 or later, could disrupt air transport throughout Europe, since many nations' planes cross German airspace. The biggest German airport, Frankfurt, is an international hub and the home of German flag carrier Lufthansa.

GdF said it would announce the stoppage 24 hours in advance. The strikers are demanding that Deutsche Flugsicherung (DFS), the federally owned air traffic control company, airports drop plans to reduce its contributions to staff pensions.

German controllers have never held a strike at all 16 German airports at the same time, though wildcat strikes in the 1970s led to major disruptions in air transport.(dpa)