Rushdie, French philosopher Bernard Henri-Levy and exiled Bangladeshi writer Taslima Nasreen were among those putting their names to the statement, to be published on Wednesday in the French weekly Charlie Hebdo, one of several French newspapers which reprinted the controversial cartoons.
"After having overcome fascism, Nazism, and Stalinism, the world now faces a new global threat: Islamism," they wrote.
"We, writers, journalists, intellectuals, call for resistance to religious totalitarianism and for the promotion of freedom, equal opportunity and secular values for all."
The cartoons triggered angry
protests across the Muslim world
They added that the clashes over the caricatures "revealed the necessity of the struggle for these universal values. The struggle will not be won by arms, but in the ideological field.
"It is not a clash of civilisations nor an antagonism of West and East that we are witnessing, but a global struggle that confronts democrats and theocrats."
The publication of the cartoons, first printed by the Danish daily newspaper Jyllands-Posten last September then reprinted by several European outlets, sparked violent, sometimes deadly, demonstrations in the Muslim world in February.
Some Western governments, media and intellectuals said the reaction was a threat to their attachment to the freedom of expression.
Muslim governments and media countered by saying it offended their religion, and some groups said it violated an Islamic custom banning images of God or Muhammad.
India-born British writer Rushdie was in a better position than most to comment on the controversy, having been made the target for murder under an Iranian fatwa for his 1998 novel The Satanic Verses, which gives an irreverent characterisation of Muhammad.
The others who signed the statement were: Somali-born Dutch feminist, writer and filmmaker Ayaan Hirsi Ali; Iranian writer Chahla Chafiq, who is exiled in France; French writer Caroline Fourest; Irshad Manji, a Ugandan refugee and writer living in Canada; Mehdi Mozaffari, an Iranian academic exiled in Denmark; Maryam Namazie, an Iranian writer living in Britain; Antoine Sfeir, director of a French review examining the Middle East; Charlie Hebdo, director Philippe Val; and Ibn Warraq, a US academic of Indian and Pakistani origin who wrote a book titled Why I Am not a Muslim.
"We, writers, journalists, intellectuals, call for resistance to religious totalitarianism and for the promotion of freedom, equal opportunity and secular values for all"
The statement said: "Like all totalitarianisms, Islamism is nurtured by fears and frustrations", but added that nothing justifies the hatred it engenders.
"Islamism is a reactionary ideology which kills equality, freedom and secularism wherever it is present."
They called for the universal right to lift the oppressed and discriminated out of the "Islamists' domination" and said "we refuse to renounce our critical spirit out of fear of being accused of Islamophobia."