The protest continues to grow – over a free speech award to Charlie Hebdo.

Earlier this week, six authors withdrew from the PEN American Centre’s annual gala – in response to the organization’s decision to give the French satirical magazine its Freedom of Expression Courage Award.

Almost 150 other writers have now joined the protest and have signed an open letter which is critical of the PEN decision.

The letter reads:

“It is clear and inarguable that the murder of a dozen people in the Charlie Hebdo offices is sickening and tragic. What is neither clear nor inarguable is the decision to confer an award for courageous freedom of expression on Charlie Hebdo, or what criteria, exactly, were used to make that decision.

Power and prestige are elements that must be recognized in considering almost any form of discourse, including satire. The inequities between the person holding the pen – and the subject fixed on paper by that pen – cannot, and must not, be ignored.

To the section of the French population that is already marginalized, embattled, and victimized, a population that is shaped by the legacy of France’s various colonial enterprises, and that contains a large percentage of devout Muslims, Charlie Hebdo’s cartoons of The Prophet must be seen as being intended to cause further humiliation and suffering.”

Salman Rushdie, a famous subject of a fatwa after publishing “The Satanic Verses, ” has joined those defending the PEN decision.

In a letter to the organization he says, “This issue has nothing to do with an oppressed and disadvantaged minority. It has everything to do with the battle against fanatical Islam, which is highly organized, well-funded, and which seeks to terrify us all, Muslims and non-Muslims, into cowed silence.”

On Monday, PEN America’s president, Andrew Solomon said “the award does not agree with the content of what they expressed. It’s a courage award, not a content award.”

The gala is set for May 5th.