STOCKHOLM (REUTERS) - Swedish football clubs Hammarby and Djurgarden have been summoned to attend a crisis meeting after an explosive device was found outside Stockholm's new Tele2 arena, which the two sides are due to share.

"According to our technicians, it was operational and not a dummy," police spokesman Sven-Olof Olsson told reporters.

The device was found on Thursday as a Djurgarden masters team were preparing for a charity match, which rival Hammarby fans saw as an attempt to "claim" the arena by playing the first game there.

Hammarby are due to face Orgryte in the first official game at the new arena on Saturday, and Djurgarden rejected claims that they had tried to hijack the premiere.

"It was a test event," Djurgarden's communications manager Gunnar Gidelfeldt told newspaper Sportbladet.

"We did not inaugurate the stadium. A premiere is supposed to be an important football game."

The charity match was cancelled as the explosive device was investigated and dealt with, and representatives of both clubs have been called to a meeting with police.