The Football Association has launched an investigation after West Brom's FA Cup defeat by local rivals Wolves was suspended for 38 minutes because of "completely unacceptable" crowd trouble at The Hawthorns.

Police said two arrests were made and a man is in hospital with head injuries.

Trouble flared after Wolves took a 2-0 lead in the 78th minute.

Fights began in the corner of the West Stand and Birmingham Road end while missiles were thrown elsewhere.

As fans spilled on to the pitch, players returned to the dressing rooms.

"The disorder that occurred at the Black Country derby between West Bromwich Albion and Wolverhampton Wanderers is completely unacceptable," said the FA in a statement.

"Safety and security are of the utmost importance, and the behaviour of those involved is dangerous and inexcusable.

"We will be investigating these serious incidents and appropriate action will be taken."

West Brom said they "condemn in the strongest terms the unsavoury scenes" and that they would work with West Midlands Police and the FA to help their investigations.

The Championship club added that "any individual involved in the disorder will be subject to a club ban".

Once police had restored order the players returned to the field shortly after 13:50 GMT to begin a warm-up, with the game resuming 10 minutes later.

"We've had extra officers at this local derby and they responded immediately as disorder in the stands caused fans to spill onto the pitch," said West Midlands Police.

"Two people were arrested for public order offences. Another man was arrested before the game for possession of an offensive weapon."