The SPFL said that, although “it was fantastic to have over 80,000 supporters attend” the League Cup semi-finals, “the large-scale, organised and illegal pyrotechnics displays which were carried out by a small minority of supporters before the Celtic v Aberdeen and Motherwell v Rangers matches were totally unacceptable”.
The governing body said in a statement: “This irresponsible behaviour caused significant inconvenience to thousands of fans at the game and to supporters watching worldwide.
“The SPFL, Scottish FA, Police Scotland and other organisations have been clear that such use of pyrotechnics is illegal and poses clear dangers and health and safety risks to fellow supporters, players and those working at matches.
“There have been a number of complaints from supporters about these incidents and the SPFL and Scottish FA have been in ongoing discussions with the clubs involved in the weeks since the semi-finals.”
Celtic are due to face Rangers in the League Cup final at the national stadium on 15 December, when a capacity crowd is expected.
“The SPFL and Scottish FA will continue to work closely with the finalists in the build up to this showpiece occasion to reinforce the importance of ensuring a safe and enjoyable match day experience for all supporters, in the context of what is now an ongoing disciplinary process,” the SPFL added.
League rules state that each club, “so far as is reasonably practicable”, must ensure that supporters do not engage in “unacceptable conduct”; that they identify any fans who engage in such conduct at a match; and take “proportionate disciplinary measures” on such supporters.