Freedom of expression advocacy group PEN America sent an open letter on Sunday to President Abdel-Fattah El-Sisi and Egyptian MPs – signed by over 120 renowned writers and artists, including American filmmaker Woody Allen, Paul Auster and Orhan Pamuk – urging the release of jailed Egyptian novelist Ahmed Naji.

The letter was sent by PEN America a few days before its annual Literary Gala, which will be held in New York on 16 May.

The organisation will honour the author in absentia with the PEN/Barbey Freedom to Write Award in recognition of his struggle in the face of adversity for the right to freedom of expression, according to the organisation's website.

In the letter, petitioners denounced Naji’s jailing, saying that "writing is not a crime."

The list of the petitioners include American literary icons Robert Caro and Philip Roth, bestselling authors Michael Chabon and Chimamanda Adichie, cultural luminary Stephen Sondheim, Turkish Elif Shafak, Nigerian-American Teju Cole, Indian Siddhartha Deb, among others.

The letter says that Naji’s references to sex and drugs are "subjects so relevant to contemporary life that they are addressed through creative expression worldwide, and clearly fall within Egypt’s constitutional protections for artistic freedom."

In Februray, Naji received a sentence of two years in jail by an appeal misdemeanour courtd for “violating public decency” and using erotic language in a chapter from his latest novel The Use of Life, which was published in state-owned literary newspaper Akhbar El-Adab.

Naji was cleared in January of the same charges by a lower misdemeanour court.

The 31-year-old novelist is serving his sentence in Tora prison in south Cairo.

Nagy's defence team is currently appealing the sentence before the Court of Cassation, Egypt's highest appeals court.

The letter deemed Naji’s sentencing "emblematic of the Egyptian government’s deeply troubling crackdown on free expression," saying that over the past year, Egyptian authorities closed cultural centres, raided an art gallery and publishing house, and imposed prison terms on several other artists, including film producer Rana El-Sobky and poet Fatima Naoot.

According to Egypt's Press Syndicate, there are at least 27 journalists in prison on various criminal charges. The union says these journalists are jailed or face criminal procedures in cases ultimately related to freedom of expression.

Egypt comes second to China in jailing writers, according to the Committee To Protect Journalists.

The list of the petitioners include prominent American novelist Philip Roth, Turkish Elif Shafak, Teju Cole and Siddhartha Deb, among others.