The As-Sahab Media Foundation, which functions as al-Qaida's media centre, published a call for Muslims to "take revenge" on Denmark and Sweden for the Quran-burning protests carried out over the past few months, in an announcement titled "The obligation to attack the aggressive peoples".
"Denmark and Sweden are two small, despicable countries that amount to no more than two small spots on the world map," the three-page document reads. "People of Islam in Sweden, Denmark and all of Europe, the duty of revenge is placed upon you."
Tore Refslund Hamming, a senior fellow at the International Centre for the Study of Radicalisation at the UK's King's College, described the document as "the most direct call from militant Islamists to carry out a terror attack against Denmark since the Mohammed crisis" in a thread in Danish on the communication app X, formerly known as Twitter.
But Swedish terrorism researcher Hans Brun, also based at King's College, downplayed the significance of the threats.
"This is really not anything new, but just another call to people around the world to exact revenge, and it's directed at lone actors," he told Sweden's TT newswire, adding that he did not believe that al-Qaida was itself planning an attack.
"You could look at it as a call to action. If this was something they had organised themselves, they would not have announced it in advance like this. You should also remember that al-Qaida these days is significantly weakened."
Brun said that al-Qaida's statement did not affect the overall security situation, with the biggest impact likely to be felt by Danish and Swedish diplomats working in the Middle East, who might need to take extra precautions.
Swedish security services have previously said that the terror threat against Sweden has increased as a result of Quran-burning demonstrations, although there have generally been more counter-protesters present at the demonstrations than actual protesters.
The UK government on the weekend changed its advice for people travelling to Sweden, saying it was now "very likely" that terror groups were planning an attack.