Berlin, May 4 (IANS): The English Football Association (FA) has started an official inquiry into the attempt to create a European Super League, which involved six top-flight English clubs.

The FA said in a statement on Monday that it "wrote to all of the clubs to formally request all relevant information and evidence regarding their participation" last week, reports DPA.

The association is also discussing how to prevent new projects such as the Super League from happening "now and in the future".

"Once we have the required information, we will consider what appropriate steps to take. Clearly what happened was unacceptable and could have caused great harm to clubs at every level of English football," the FA said.

The FA recognised the fans "played a vital and impactful role" with protests that helped stop the Super League from happening but condemned the "violent and criminal behaviour" of Manchester United fans.

Fans broke into the stadium on Sunday and invaded the pitch in protest against club owners, the Glazer family, while outside the ground bottles and barriers were thrown at police officers and horses.

The actions caused the Manchester United game against Liverpool to be postponed.