Police were called to Longsight on Wednesday afternoon to reports of a suspected stabbing.
Officers were scrambled to the Lidl supermarket at the junction of the A6 and Stanley Grove at 3.20pm, after receiving reports of an attack.
But when they arrived, they discovered no victim and no weapon.
Security staff at the supermarket were also not aware of any incident having occurred.
A group of youths however, were caught fighting nearby.
Residents reported seeing a large emergency response at the supermarket and on surrounding streets, including nearby Norman Grove.
A spokesman for GMP confirmed that two teenagers were arrested on suspicion of a section 18 offence.
