Seven Muslims were arrested in the Republic today over an alleged plot to assassinate a Swedish cartoonist who depicted the Prophet Mohammed with the body of a dog, police said.

Al Qaeda put a $100,000-dollar bounty on the head of cartoonist Lars Vilks after a newspaper published his cartoon.

The four men and three women were detained after an investigation involving European security agencies and the United States' CIA and FBI.

Mr Vilks, who lives in an isolated area of Sweden, was put under police protection after threats were made against his life.

When al Qaida put the bounty on the cartoonist's head in 2007 it offered a 50% bonus if Mr Vilks was "slaughtered like a lamb" by having his throat cut, while another 50,000 dollars was put on the life of Ulf Johansson, editor-in-chief of Nerikes Allehanda, the local newspaper which printed the cartoon.

However those arrested are not believed to be members of the terrorist group.

It understood some have converted to the Muslim faith.

The arrests were made at around 10am as officers conducted a number of raids.

Gardai said the operation was supported by members from National Support Services and the Republic's anti-terrorist Special Detective Unit.

A Garda spokesman added: "Throughout the investigation An Garda Siochana has been working closely with law enforcement agencies in the United States and in a number of European countries."