Six people have been arrested after disruption at an FA Cup match between West Bromwich Albion and Wolverhampton Wanderers.
The players were taken off the pitch in the 83rd minute on Sunday, soon after Wolves scored their second goal to lead 2-0 in the Black Country derby.
Five people were arrested for public order offences after the disturbance and another was held before kick-off for having an offensive weapon, while a man was taken to hospital with head injuries, West Midlands Police said.
Pictures showed a supporter with blood pouring from a head wound being helped away by police.
A total of four people were treated after the disruption, a West Midlands Ambulance spokesperson said.
The FA announced an immediate investigation into the disorder.
Earlier, officers and security staff rushed to a corner of the ground supposedly holding home fans as the disturbance developed and fans spilled onto the pitch, while the players were ushered off the pitch.
There appeared to be a lot of pushing and shoving in the stand.
Some West Brom players were concerned for family members seated nearby and West Brom's Kyle Bartley was filmed taking two young children into the tunnel as police tried to restore order.
Referee Thomas Bramall eventually took the players from both teams back to the dressing rooms.
There had earlier been pockets of trouble in other parts of the ground.
Flares were thrown in the away section after Wolves opened the scoring in the first half and objects were also thrown at Wolves' Tommy Doyle as he prepared to take a corner.
The players returned to the pitch to warm up after about 15 minutes, and the match re-started after a break of around half an hour with 12 minutes of the game remaining.
West Midlands Police said in a statement: "Five people have now been arrested for public order offences relating to the disorder in the ground.
"Another man was arrested for possession of an offensive weapon prior to the match outside of the ground."
The FA said in a statement posted on X that it is launching an investigation into the "serious incidents", which it called "completely unacceptable" and the behaviour of those involved "dangerous and inexcusable".
ITV's pitchside reporter Katie Shanahan said at the time of the delay that the referee was having to wait to get "the go-ahead from the safety team".
Police and security officers surrounded the pitch as the players left after Wolves eventually beat West Brom 2-0.