Nearly 300 US servicemen who take part in the international exercise `Cooperative Key - 2001`started to go back to their permanent bases on September 14, the Director of the Press Center colonel Stoyanov announced. The participants were ordered to return. About 100 servicemen mainly from the operational body continue their participation in the exercise, though. At 12 noon, September 14, the participants in `Cooperative Key – 2001` honored with one minute silence the memory of the innocent victims from US. The national flags of all participating countries were lowered. Flights took place as part of the exercises.