By Philip O'Connor
STOCKHOLM (Reuters) - Djurgardens manager Magnus Pehrsson has quit following threats from supporters, the Swedish top-flight club said in a statement on Friday.
Swedish soccer has been plagued by violent incidents in recent years, and Pehrsson's decision prompted a news conference by Swedish prime minister Fredrik Reinfeldt who stood on the Djurgarden terraces as a teenager.
"It cannot be that nothing happens and they are allowed to continue," Reinfeldt said of the behaviour of a minority of troublesome fans. "It is not acceptable that these advocates of violence set the agenda."
Reinfeldt said there were many options open to his government.
"We're often asked for new legislation, but we can make whatever laws we like - if we don't use them, they won't make any difference," he said.
"I'd like to point out that it is criminal to threaten others. That must be followed up."
Several matches have been disrupted in recent years due to fans throwing fireworks at officials and a derby between Malmo and Helsingborg was abandoned when goalkeeper Par Hansson was attacked by a fan.
A recent TV documentary also alleged that hooligans from the "firm" of Stockholm club AIK had infiltrated the board.
A former player who appeared over 100 times for the club before taking over as manager in 2011, 37-year-old Pehrsson decided to resign following threats made to him following last weekend's defeat by champions Elfsborg.
That defeat left his team bottom of the table with just one point from four games, a single goal scored and 10 conceded.
"The threats were expressed via telephone after the loss to Elfsborg, but also during an unannounced visit during the A team's training session on Tuesday," a club statement said.
"Three people from an unofficial supporters' group expressed their disappointment about the sporting results. At the same time, they pointed out in a threatening manner what consequences continued poor results would have for Magnus personally."
The threats have been reported to the police.
"The way the situation developed after Monday's and Tuesday's events, my position as manager and as a person was untenable, and I have taken the decision to leave the club," said Pehrsson.
Djurgarden Football chairman Tommy Jacobson has also resigned.
"Sad is too mild a word - it's tragic that these kinds of forces can have such an influence," he said in a statement.
"That Magnus felt he had to resign was the last straw for me," Jacobson added.
"That there are people who totally go against the both the club's and society's democratic principles is completely unacceptable for me in my role as chairman. I hope it starts an examination in these supporter circles."
Djurgardens have also had a home game abandoned due to crowd trouble, when a player from Mjallby was struck by an object thrown from the crowd as he celebrated a goal.
Police have said they are confident of identifying the three individuals who allegedly threatened Pehrsson.
"I think we'll get the three names without help from the general public, we have a good starting point," police investigator Ann-Britt Furugard told newspaper Sportbladet.
(Editing by Ed Osmond)