The head of an al-Qaida-led group in Iraq offered $100,000 for the killing of Swedish cartoonist Lars Vilks over his drawing depicting the Prophet Mohammad.
"From now on we announce the call to shed the blood of the Lars who dared to insult our Prophet... and during this munificent month we announce an award worth 100,000 to the person who kills this infidel criminal," said Abu Omar al-Baghdadi, leader of the self-styled Islamic State in Iraq, in an audiotape posted on a Web site on Saturday.
"The award will be increased to $150,000 if he were to be slaughtered like a lamb."
Sweden's daily Nerikes Allehanda published the drawing last month. Vilks' drawing was part of a series which art galleries in Sweden had declined to display.
The newspaper published the image, depicting the head of the Prophet on the body of a dog, in what it called a defense of free speech.
Muslim countries including Iran, Pakistan and Afghanistan have expressed anger over the caricature.
Iran, the first country to protest against the publication of the drawing on Aug. 27, summoned Sweden's charge d'affaires in Tehran to complain. Muslims believe images of the Prophet are forbidden and also consider dogs to be impure.
Last year, Muslims around the world launched a firestorm of protest after a Danish newspaper published cartoons of the Prophet Mohammad that were reprinted by other European newspapers.