Neil Gaiman, Ian McEwan and Jonathan Franzen have put their names to a letter calling on China’s president Xi Jinping to release the Chinese writers who “are languishing in jail for the crime of expressing their opinions”.

In an open letter to Xi, published just before the Chinese president’s first US state visit this week, more than 40 authors have come together to express their “deepest concern about the deteriorating state of free expression in China”. The letter highlights four cases of writers who are currently imprisoned in China: Uighur scholar Ilham Tohti, sentenced to life in prison “for voicing his views online about the treatment of Uighurs”, according to PEN American Center; investigative journalist Gao Yu, a 71-year-old in ill health who was sentenced to seven years in prison earlier this year; literary critic and writer Liu Xiaobo, sentenced to an 11-year term in 2009 over calls for political reform; and his wife Liu Xia, a painter, poet and photographer who has been under house arrest for nearly five years, according to PEN.

But the signatories, who also include Xiaolu Guo, Jennifer Egan, Jeffrey Eugenides, Paul Auster and Dava Sobel, say in their letter to Xi that there are at least 47 writers and journalists currently in jail in China, and urged the president to release them.

“The imprisonment of writers and journalists damages China’s image abroad and undercuts its ambition to be a strong and respected partner on the world stage. So too does broad official censorship of literature, the news media, and the internet and telecommunications technologies, as it prevents Chinese citizens from accessing accurate news and information that is in the public interest, and stifles the creativity and diversity of viewpoints that are essential to building a dynamic and competitive economy and culture,” they write.

“To that end, Mr President, we urge you to release the Chinese writers and journalists who are languishing in jail for the crime of expressing their opinions, and to take immediate steps to defend and protect the rights of all Chinese citizens to communicate and access information freely.”

In May, authors including Auster, Franzen, AM Homes and Francine Prose had joined PEN and Chinese writers and publishers Xiaolu Guo, Bao Pu and Murong Xuecun in a rally highlighting China’s imprisoned and silenced writers on the steps of the New York Public Library. They read from the works of those who had been incarcerated, including Liu Xiaobo, Liu Xia, Ai Weiwei and Ilham Tohti, calling for the release of “all those imprisoned for their words in China”.

Suzanne Nossel, executive director at PEN American Center, which released the open letter, said that China’s president had “stepped up his crackdown on dissent in recent months, trying to muffle anxieties about China’s economy and banking on the idea that there is too much at stake in terms of US-China economic and security relations for human rights to interfere with his trip”.

Xi arrives in the US on 22 September. This week he will attend a summit in Seattle along with major US technology companies including Google and Facebook, as well as meeting US president Barack Obama later in the week and then addressing the UN general assembly in New York.

“With all the focus on trying to foster mutual understanding amidst Chinese muscle-flexing in Asia, in global markets, and in cyberspace, it’s essential for American leaders to remember while listening to the Party line that some of the most forward-looking and open-minded Chinese thinkers are sitting in jail and untold others are deterred from voicing challenges for fear of being threatened, detained, or sentenced to long prison terms,” said Nossel.