Footage has emerged of violent clashes, said to be between Rangers and Wigan fans, after the Latics friendly in Glasgow yesterday.
Eyewitnesses say there was a heavy police presence outside Glasgow Central station, after the game which saw Wigan lose 3-0 to Steven Gerrard's side.
And a video has been posted online showing extended fighting between supporters in one of the streets beside the station.
One supporter is shown slumped on the ground in Hope Street as rivals clash outside a betting shop.
A Police Scotland spokesman said: "We were called at around 6.40pm to a large-scale disturbance in Hope Street, near to the junction with Argyle Street, near to Glasgow Central station.
"As a result two men were taken to hospital with minor injuries.
"We are liaising with the British Transport Police and our enquiries are ongoing."
Police have confirmed that the investigation will probe the likelihood that rival fans were involved in the violence, which saw blows exchanged and bins and advertising hoardings thrown down the street.
But it is not thought that the clash represented any organised fight between followers of both clubs.
No arrests have been made so far.
An onlooker said the disturbance also appeared to centre on the Sir John Moore Wetherspoons pub, close to the station.
He added: "There was an initially very large police presence. The pub has been damaged internally and was closed.
"The issue appears to have been a fight between Rangers football fans and the visiting Wigan Athletic fans."