Officers are investigating whether one of the men fell from a 12th floor balcony of the 19-storey Donside Court, in the Tillydrone area of the city.
Emergency services were called to the building at about 20:15 on Tuesday evening.
A witness has described hearing a woman screaming "help me, help me" before police arrived.
Police Scotland said it believed the incident was contained and there was not a threat to the wider community.
A blue forensics tent had been erected inside a police cordon at the foot of the building, close to the main entrance.
An eyewitness said they saw a man fall from the 12th floor of the building, which police confirmed they were pursuing as a line of inquiry.
Another witness, Toni Dey, 19, who lives a short distance away in Gordon's Mills Road, said she heard screaming from the block.
The mother of two said: "I heard some girl screaming 'Help me, help me', then about 10 minutes after I heard loads of screaming and shouting.
"I didn't call the police as I thought it was kids messing around, then I heard loads of police.
"It's very scary to think that something like that had happened. All I kept thinking was 'Why was that poor girl shouting help me?', and about a two-minute walk out my back door.
"I just moved in here in May and it's been so quiet. I was