Hammarby fans have insisted they did not infiltrate the Celtic section of the Friends Arena following clashes during the Europa League showdown with AIK Stockholm.
Neil Lennon 's side cruised through to the group stage with a 4-1 win in Sweden, but the tie was marred by ugly scenes after security entered the away section occupied by Hoops fans leading to ugly clashes.
Celtic made clear after the game they laid the blame at supporters of AIK's city rivals Hammarby, who had managed to secure tickets for the Celtic section of the ground.
A spokesman for the Parkhead club stated: "We are aware that a number of Swedish supporters entered the area for visiting fans and we are currently investigating events.
"It was clear many Hammarby fans were in the Celtic sections and this was raised by Celtic officials before the match.
"A lot of Swedish fans managed to infiltrate the away section which we believe was a major factor in the issues which arose, there was a lack of control at the access points to the Celtic section.”
However, Hammarby fans have denied deliberately causing trouble.
Their supporters group, the Bajen Fans' spokesman, Kalle Strandberg, said: "We have had no cooperation whatsoever with Celtic fans.
"I don't know anything about it. It is possible there were Hammarby supporters there, but it wasn't organised by us. If that's the case, it would be about ultras or indviduals."
