The RFL are to investigate the crowd trouble that marred the end of the Challenge Cup semi-final between Castleford and Widnes on Sunday.
Around 100 supporters from the Widnes end of the ground entered the pitch after the hooter, and made their way towards the Castleford fans in the opposite side.
Several incidents have been reported extensively on social media in the hours since the game, which ended in a comfortable 28-6 win for Castleford in front of a sell out 12,005 crowd at Leigh Sports Village.
In a statement, the RFL said it would await reports from the stadium, the police and the two clubs before deciding what action to take.
RFL Chief Executive Nigel Wood said: “The sport has every right to be disappointed with the behaviour of a minority of Widnes fans. We will work with the clubs to identify any supporters who encroached onto the pitch. There is no place for such behaviour in Rugby League.
“True Rugby League supporters are renowned for their good nature at all occasions such as this and we will not hesitate to use whatever measures are available to us to protect these precious values.”