A Swedish court on Tuesday overturned a police move to ban two gatherings where protesters had planned to burn Qurans, as five suspected Islamists were arrested for plotting a "terrorist act" over a similar demonstration.
The burning of Islam's holy book outside Turkey's embassy in Stockholm in January angered the Muslim world, sparking weeks of protests, calls for a boycott of Swedish goods, and holding up Sweden's Nato membership bid.
Swedish police then banned two subsequent similar protests planned for February on security concerns.
But the Stockholm Administrative Court overturned the decision on Tuesday, saying security risk concerns were not enough to limit the right to demonstrate.
The "police authority did not have sufficient support for its decisions," judge Eva-Lotta Hedin said, in a decision that in theory could clear the way for more such protests.
Police spokesman Ola Osterling told news agency TT that the police authority has not yet decided whether to appeal the ruling, but "we maintain that our decision was correct".
Swedish police had authorised the January protest organised by Rasmus Paludan, a Swedish-Danish activist who has already been convicted for racist abuse.
Paludan also provoked rioting in Sweden last year when he went on a tour of the country and publicly burned copies of the Quran.
But police then refused to authorise the two other requests, by a private individual and an organisation, to hold Quran burnings outside the Turkish and Iraqi embassies in Stockholm in February.
Police argued that the January protest had made Sweden "a higher priority target for attacks".
'Freedom of expression'
Paludan's Quran burning also damaged Sweden's relations with Turkey, which took particular offence that police had authorised the demonstration.
Ankara has blocked Sweden's Nato bid because of what it perceives as Stockholm's failure to crack down on Kurdish groups it views as "terrorists".
"It is clear that those who caused such a disgrace in front of our country's embassy can no longer expect any benevolence from us regarding their application for Nato membership," Turkish President Recep Tayyip Erdogan said in January.
Swedish politicians have criticised the Quran burning, but have also adamantly defended the right to freedom of expression.
"Freedom of expression is a fundamental part of democracy. But what is legal is not necessarily appropriate. Burning books that are holy to many is a deeply disrespectful act," Prime Minister Ulf Kristersson said after the January burning.
A Swedish expert in administrative law, Tom Schultz-Eklund, told AFP that the Administrative Court had interpreted Swedish law correctly.
He said he believed police would likely continue to refuse permits for Quran burning protests.
"It's just speculation from my side, but I wouldn't be surprised if the police stick to their line until there is a definitive decision from a higher court," he told AFP.
Paul Levin, director of Stockholm University's Institute for Turkish Studies, said Tuesday's court ruling "opens up for new Quran burnings."
"There are many that wish to sabotage the Nato process and a way of doing that rather effectively is to burn Korans," he told AFP.
Meanwhile, Sweden's Security Service said five suspects with links to the Islamic State (IS) were arrested early Tuesday in coordinated raids in the central towns of Eskilstuna, Linkoping and Strangnas, for allegedly planning a "terrorist act" linked to the backlash over the Quran burning.
"The current case is one of several that the Swedish Security Service has been working on... in connection with the high-profile Quran burning," Susanna Trehorning, deputy head of the security service's counterterrorism unit, said in a statement.
She said the suspects were linked to international "violent Islamic extremism".
Trehorning told AFP there "are international links in this and... connections to IS."
The Security Service said however that it did not believe that an attack had been imminent.
"The Security Service often needs to act early in order to avert a threat. We can't wait until a crime has been committed before we act," it said in the statement.