Internet provider Levonline shut down the small nationalist party Sweden Democrats' website late on Thursday following discussions with both the foreign ministry and the Saepo security police.
The party's publication SD-Kuriren issued a competition on its website on 10 January for drawings of Muhammad, just as criticism of the Danish newspaper that first published 12 cartoons of the Muslim prophet last September was beginning to swell.
The website www.sdkuriren.se, which also offered links to the Danish cartoons that have sparked violent protests across the Muslim world, reportedly moved to a new Internet provider and was still visible on Friday.
"It's true that we contacted them (Levonline) ... We presented the threat we saw" in connection with the site, Saepo spokesman Jakob Larsson told AFP.
He added however that his agency "did not tell them to shut down the site. They made that decision on their own."
A foreign ministry spokesman also acknowledged that discussions had been held with the Internet provider. Levonline refused to comment.