Swedish players warn troublemakers
"Those of you that destroy our great football are not welcome, we don't want you there," said the captains of the sixteen top flight clubs in a letter published by the players' union.
AIK's away game against Syrianska in April was called off when a firecracker went off beside an assistant referee and a ball boy was injured in crowd trouble which erupted after a sending-off.
Another match was abandoned when a supporter ran on to the field and attacked Helsinborg's goalkeeper in a derby against Malmo.
"We hope that this collective call will be a signal to break the negative trend," said the letter. Other matches have been marred by the illegal use of fireworks in the crowd.