Sweden raised its terrorism threat level a notch on Thursday, after a series of Quran desecration demonstrations that have angered Muslim political leaders and sparked international protests.
The risk of terrorism in Sweden was now at level four, or high, on the country's five-point scale.
Sweden’s Sapo domestic security service said the overall security situation has deteriorated and the risk of terrorism was raised.
Sweden has also warned citizens abroad and businesses linked to the country to “observe increased vigilance and caution” after the protests led by an asylum seeker.
Earlier this year, a far-right activist from Denmark burnt the Quran outside the Turkish embassy in Stockholm.
“We are in a deteriorating situation and this threat will continue for a long time,” Sapo chief Charlotte von Essen said.
“The threat of attacks from actors within violent Islamism has increased during the year.”
Like many Western countries, Sweden does not have blasphemy laws that prohibit the burning of religious texts.
Stockholm is now considering whether to make it illegal to set holy books on fire.
However, attempting to doing so would face domestic opposition over rights to freedom of expression.
Authorities tried refusing several protest applications this year, citing security concerns. But the courts ruled these protests were protected by Sweden's freedom of speech laws.
One of the Swedish protests took place during Eid Al Adha, close Stockholm’s largest mosque.
“The Swedish government fully understands that the Islamophobic acts committed by individuals at demonstrations in Sweden can be offensive to Muslims,” the Foreign Ministry has said previously.
“We strongly condemn these acts, which in no way reflect the views of the Swedish government.”
The Saudi-based inter-governmental Organisation of Islamic Co-operation has urged its 57 members to “take unified and collective measures to prevent” any repeat of the desecration of the holy book.
Protests against the desecrations have been held around the world.
In Denmark, where there have also been several similar desecrations, police on Wednesday said there would be “temporarily-intensified efforts at the internal Danish borders”.
The Danish government on has also said it will explore legal means to stop protests involving the desecration of holy texts.
The EU co-ordinator for combating anti-Muslim hatred said the bloc condemns Quran burning but that it is up to individual states whether to ban it.