The Secretary General of NATO, Jens Stoltenberg, said today that he regrets the loss of lives during the NATO air operation in Yugoslavia in 1999. "I extend my condolences to all the families who have lost loved ones. The purpose of NATO's air operation was also protection of civilians and we have managed to do this," he said. "We have not been able to eliminate the death of civilians. The aim of the operation however has been the establishment of peace," added Stoltenberg.