Turkish hackers have targeted more than 5,000 Swedish websites since a Swedish newspaper published caricature of the Prophet Muhammad's head on a dog's body.

Newspaper Nerikes Allehanda published the drawing by artist Lars Vilks on Aug. 19, triggering protests from Swedish Muslim groups and formal complaints from Muslim countries, including Pakistan and Iran.

Islamic law forbids any depiction of the Prophet, even favourable drawings, to prevent idolatry.

Since the drawing was published, attacks against Swedish websites from Turkey, a predominately Muslim country, have increased, said Stefan Grinneby, head of the Swedish communication watchdog Sitic's internet incident centre.

"You would need a very large police investigation to establish the connection to the prophet drawings, but considering the increase in recent weeks it is a fair assumption to make," he said.

Grinneby said some of the hacks have contained messages alluding to the drawing.

Swedish news agency TT said the website of children's cartoon Bamse was replaced by a message saying Islam's prophet had been insulted.

Kjetil Jensen, spokesman for internet service provider Proinet, said hackers from a Turkish network hit about 1,600 of their sites, replacing files with messages. Another company has had more than 3,800 sites targeted.

The artist, Vilks, said he has no regrets about the drawings, despite having a $100,000 bounty placed on his head by an insurgent leader in Iraq. He said he may convert the experience into a musical.

With files from the Associated Press