Swedish police detained a woman who sprayed an anti-Islam activist with a fire extinguisher as he staged a Quran-burning protest outside the Iranian Embassy in Stockholm.

Video of the scene showed the woman rushing up to Salwan Momika and spraying white powder towards him before she was intercepted by plainclothes police officers who led her away. Momika, who appeared stunned but unhurt on Friday, then resumed his demonstration, which had been authorised by police.

Police spokeswoman Towe Hagg said the woman, who was not identified by police, was detained on suspicion of disturbing public order and violence against a police officer.

Momika, a refugee from Iraq, has desecrated the Quran in a series of anti-Islam protests that have caused anger in many Muslim countries. Swedish police have allowed his demonstrations, citing freedom of speech while filing preliminary hate speech charges against him.

Prosecutors are investigating whether his actions are permissible under Sweden’s hate speech law, which prohibits incitement of hatred against groups or individuals based on race, religion or sexual orientation. Momika has said his protests target the religion of Islam, not Muslim people.

The Quran-burnings have sparked angry protests in Muslim countries, attacks on Swedish diplomatic missions and threats.

Sweden on Thursday raised its terrorism alert to the second-highest level, saying the country had become a priority target for armed groups.

Momika said he would continue to burn the Quran despite threats directed at him and Sweden, saying he wants to protect Sweden’s population from the messages of the Quran.

“I have freedom of speech,” Swedish news agency TT quoted him as saying.

Muslim leaders in Sweden have called on the government to find ways to stop the Quran burnings. Sweden dropped its last blasphemy laws in the 1970s and the government has said it has no intention to reintroduce them.

However, the government on Friday announced an inquiry into legal possibilities for enabling police to reject permits for demonstrations over national security concerns.

According to Justice Minister Gunnar Strommer, the inquiry will study legislation in countries such as France, Norway and the Netherlands that he said have extensive freedom of speech but “greater scope for including security in this type of assessment”