Launched on 1 September 1944, Operation Ratweek was a series of coordinated attacks on the Axis lines of communication, principally the railways, by Yugoslav partisans, the combined operations units of Land Forces Adriatic, the heavy bombers of the 15th Air Force and the light and medium bombers of the Balkan Air Force. The attacks paralysed movement of the German forces. In his memoir Eastern Approaches, Fitzroy Maclean claims this was his idea.
In September, 1944, there was a famous operation, planned by Brigadier Maclean, then commanding Allied liaison in Jugoslavia, in conjunction with Balkan Air Forces under Air Vice Marshal Elliott, and carried out by the Jugoslav Army, that aimed at disrupting all enemy lines of communication to coincide with certain operations in Italy. It was called "Ratweek"; and for the target duration of one week it was possible by action in all areas to paralyse all movement of enemy men and supplies on practically every length of line in Jugoslavia, whether in Slovenia, Croatia, Serbia, Macedonia, or elsewhere.