The men, aged 21 and 40, attended the police station voluntarily, British Transport Police (BTP) said. The force had earlier released CCTV images of two people they believed were involved in the fight.
Armed officers from the Metropolitan Police attended the central London station shortly before 5pm on Friday after reports gunshots had been fired.
Mass panic ensued in the packed station and several people were injured as thousands of people attempted to flee. Nine were taken to hospital, including one with leg injuries.
The Met said it responded to the incident as if it were a terror attack, but the station reopened when no evidence of gunfire was found.
The BTP said they believed "an altercation erupted between two men on the platform", prompting the mass exodus.
BBC producer Helen Bushby said: "I was just walking down from the BBC towards the Tube and there was a mass stampede away from the Tube as fast as they could.
"They were crying, they were screaming, they were dropping their shopping bags. It was a very panicked scene.
"People said they heard a gunshot and panic was just spreading."
Stuart Crichton, London Ambulance Service assistant director of operations, said: "We checked over and treated several patients who sustained injuries while leaving the Oxford Circus area.
"We discharged seven patients at the scene and took eight patients to two central London hospitals for minor injuries.
"We also took one patient to a major trauma centre for leg injuries."
Chief Superintendent Martin Fry said: "Thank you to everyone for bearing with us this evening and also to colleagues from all the emergency services who helped carry out a swift response.
"Our officers, alongside those from the MPS, reacted quickly and responded professionally in line with our well prepared plans.
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