Monday 16 September 2019 10:56, UK
Barnsley and Leeds say they are "working together" to assess the crowd trouble which marred Sunday's derby at Oakwell.
South Yorkshire Police are also understood to have launched an investigation following the arrest of three people on suspicion of public order offences and one for assault.
A spokesperson for both clubs said: "Barnsley Football Club and Leeds United Football Club are greatly disappointed by reports of violence at Sunday's game and will be working together to assess the matter."
Leeds fans clashed with stewards in the away end towards the end of the match and, in a separate incident, fighting also broke out in the east stand.
Leeds scored two goals in the final eight minutes to clinch a 2-0 win and return to the top of the Sky Bet Championship.
Arsenal loanee Eddie Nketiah opened the scoring in the 84th minute before winning a penalty five minutes later, which Mateusz Klich converted.
