Six trainee army officers have been caught with cocaine just days before they were due to be given the rank of lieutenant.
The army discovered a small quantity of the drug while the trainee officers were on a 100-kilometre route march.
During questioning, six men belonging to the fortress troops admitted to having taken the drug at least once, according to the army. Three of them admitted to having taken cocaine for the first time during their four-month military stint.
One of the six trainees allegedly supplied the cocaine to the others, after acquiring the drug during a weekend furlough.
"One of the trainees managed to set up a proper cocaine trade during officers school," said Marco Oswald, an army spokesman.
The defence ministry refuses to give out further details while the investigation is still underway.
The six men were all due to be promoted to the rank of lieutenant in a few days' time, but their military career could well be over. "It is obvious to me that we cannot promote these men," said Jacques Dousse, head of the army's land forces.
"This case is on a scale I have never seen before. As chief of the land forces, I have never come across a drug case of this size within our ranks. Especially not concerning hard drugs like cocaine."
The Swiss army has been paying more attention to drug usage within its ranks in the past few years. It is estimated that one in three recruits smoke marijuana or hashish and that number is thought to be rising.
Many of these recruits also often try so-called "soft" drugs during their first stint with the army, according to its psycho-pedagogical service. Marijuana or hashish usage also increases for casual smokers.
Dousse said any type of drug use is unacceptable in the army, particularly among officers. "Officers have responsibilities, including making sure our army is drug-free, and they have to show the right example."
Service in Switzerland's militia-based army is compulsory for all able-bodied Swiss men. Soldiers are selected to attend officers' school according to their ability after serving as non-commissioned officers, and those chosen cannot refuse to attend.
swissinfo with agencies