In a statement, the police said they had recently stopped two such shipments.
In one set of six mattresses they found 206 packages of pentolite, almost 800 meters of detonating cord, and a PKT machine gun.
In another mattress shipment, they found 177 kilos worth of explosives. This is the first time the police have detected Colombia's illegal groups making transfers inside "comfortable mattresses for sale in specialized stores." Read the full press release - with additional pictures - here.
The seizure comes as the FARC is accused of stepping up its bombing campaign amid increased military presence along drug routes.