The FA tonight launched an investigation into events inside Villa Park.
Trouble flared before the 5.30pm local derby outside The Witton Arms pub in Aston.
Police and ambulance crews were called to the scene at approximately 4.30pm after reports of disorder between fans.
West Midlands Police will now carry out a full investigation into the violence before the match, which saw Aston Villa win 2-0.
Chief Superintendent Chris Johnson from West Midlands Police said: "Officers were required to disperse a number of people at the Witton Arms pub ahead of this evening's match between Aston Villa and West Bromwich Albion following reports of disorder.
"Two people were arrested from the pub and the immediate surrounding area in Witton Road and were taken into custody."
Fans tweeting from the scene described the pub as a 'war zone' and advised other supporters to stay away.
One fan tweeted:
Another posted: "Witton Arms is a war zone."
There was further disorder in the ground after the second goal, scored in the 85th minute by former Albion player Scott Sinclair.
Albion fans are reported to have ripped seats from The North Stand and thrown them from the upper tier onto celebrating Villa fans below and referee Anthony Taylor was forced to stop the match as fans invaded the pitch.
After play resumed Villa saw the game out before another pitch invasion followed on the final whistle.
The club could now face a Football Association inquiry.
Anyone who saw anything is asked to call police on 101 or Crimestoppers, anonymously, on 0800 555 111.
Reaction on Twitter: