STOCKHOLM Sweden has ramped up security at embassies and other missions due to an incease in threats against Swedish interests abroad, Foreign Minister Tobias Billstrom told TT news agency on Friday.

Sweden raised its terrorist alert to the second highest level on Thursday, saying it had thwarted attacks after Koran burnings and other acts against Islam's holiest text outraged Muslims and triggered threats from jihadists.

Billstrom told TT that Sweden has increased security at embassies and other missions, without going into detail for security reasons.

"But the safety of the Ministry of Foreign Affairs' staff is the highest priority," he said, adding that the safety of families of diplomats and local staff was also taken into account.

"So there are different categories that are affected by this security work that is now being intensified," he said.

Billstrom did not immediately reply to a request for comment.

Anti-Islam activists have damaged several copies of the Koran in recent months in Sweden and also in Denmark, two of the most liberal countries in the world that allow trenchant criticism of religion in the name of free speech.

But many Muslims view desecrating the Koran, which they see as the literal word of God, as a grave offence. A media outlet linked to militant group al Qaeda has urged violent retribution.

(Reporting by Johan Ahlander; Editing by Angus MacSwan)