Salman Rushdie has defended the right to criticise and satirise religion after Wednesday's attack on satirical newspaper Charlie Hebdo that killed 12 people and left 11 others wounded.

The author, who has previously written a book criticising Islam, said in a statement that "religious totalitarianism" had caused a "deadly mutation" in Islam and that this was a factor in Wednesday's attack.  

He went on to claim religion is a "medieval form of unreason" that "when combined with modern weaponry becomes a real threat to our freedoms".

For this reason, he alleged that religion should continue to be subject to criticism and satire.  

"I stand with Charlie Hebdo, as we all must, to defend the art of satire, which has always been a force for liberty and against tyranny, dishonesty and stupidity," he said.

"'Respect for religion' has become a code phrase meaning 'fear of religion.' Religions, like all other ideas, deserve criticism, satire, and, yes, our fearless disrespect."

Rushdie himself was the subject of a fatwa that was issued by the late Ayatollah Khomeini of Iran in 1989. Khomeini offered a $2.8 million reward for the death of Rushdie for his work, "The Satanic Verses," which Khomeini viewed as "blasphemous." In 2012, the Huffington Post reported that 15 Khordad Foundation had increased that reward to $3.3 million.

His statement condemning Wednesday's attack was originally posted to the PEN literary network's website. Rushdie is a past recipient of PEN's Pinter Prize and was a signatory of PEN America's official response to the attacks, which called upon "responsible authorities and institutions to redouble their efforts to protect those working on the front lines of free expression worldwide." 

France is still reeling from the attack in which three masked gunmen attacked the Charlie Hebdo offices in Paris and opened fire during an editorial meeting.

The police named the perpetrators as Said Kouachi, born in 1980, Cherif Kouachi, born in 1982, both from Paris, and Hamyd Mourad, born in 1996.

Mourad turned himself in to police soon after the attack, reportedly after seeing his name in media reports and on social media.  The other two have reportedly been killed after a major manhunt and police operation that tracked them down to a printing house in the town of Dammartin-en-Goele near Charles de Gaulle International Airport.