NEW YORK (AP) — Exiled Chinese author Yu Jie joined other writers including Salman Rushdie on the 20th observance of World Press Freedom Day in appealing to China to live up to its own constitution and laws guaranteeing freedom of expression, and calling on the public to put pressure on governments that crack down on writers.

Yu and other writers and activists were on a PEN International panel Friday highlighting a report on trends of the last five years in China’s crackdown on free expression. It also marked the 20th anniversary of the U.N. General Assembly’s designation of May 3 as World Press Freedom Day.

Other writers who signed onto the appeal included Mario Vargas Llosa, J.M. Coetzee, Marjane Satrapi, Wole Soyinka, Nadine Gordimer, Andrei Bitov and Tomas Transtromer.

Yu came to the U.S. in January after receiving asylum. He was detained several times in China last year and said he was beaten so badly that he passed out. He has said he thinks Chinese authorities will not allow him back because he has accused them of torture.

“The Chinese Communist Party’s secret police hooded me and kidnapped me,” said Yu, who wrote a critical biography of Prime Minister Wen Jiabao, titled “China’s Best Actor.”

“And they bent back my fingers one by one and said that as my fingers typed 10 million characters in articles on the computer opposing the Chinese Communist Party, all 10 of my fingers should be broken. They said that they only needed to make a phone call to their senior, and then they could dig a hole and bury me alive in half an hour,” he said Friday.

“In numerous nightmares, I have dreamed of the torture I experienced. That is China,” Yu said.

Calls to China’s U.N. Mission seeking comment Friday were not returned. In January 2012, when Yu left China, Chinese Foreign Ministry spokesman Liu Weimin said he was unaware of Yu and reports of his departure.

“These regimes do not like being highlighted,” Rushdie said. He said that when PEN focuses on a writer who has been imprisoned, 90 percent of them are freed within six months.

Is the effort worth it? “The people in trouble think this is important,” Rushdie said, adding that he knew this from his own ordeal.

Rushie, whose 1988 novel “The Satanic Verses” offended Muslims worldwide with its satirical portray of their prophet. Rushie had to move to the United States and live under guard for years due to death threats over the book, including a 1989 fatwa issued by Iran’s supreme leader, Ayatollah Ruhollah Khomeini.

The most prominent among those imprisoned in China is Liu Xiaobo, the literary critic, writer, professor, and activist who received the 2010 Nobel Peace Prize, and a close friend of Yu.

Other observations of World Press Freedom Day included:

The Committee to Protect Journalists, based in New York, tallied 17 journalists killed worldwide so far this year, and 232 imprisoned.

The France-based Reporters Without Borders group named 39 “Predators of Freedom of Information” worldwide — presidents, politicians, religious leaders, militias and criminal organizations that the group says censor, imprison, kidnap, torture and kill journalists and other news providers.

Reporters without Borders said it had added five new “predators” to the list: new Chinese President Xi Jinping, the Syrian Jihadi group Jabhat Al-Nosra, members and supporters of Egypt’s Muslim Brotherhood, Pakistan’s Baloch armed groups, and Maldives’ religious extremists.

Amnesty International announced in London that Syria’s government and elements of its rebel movement are deliberately targeting journalists, releasing a report which had blame for both sides in the country’s civil war. The London-based rights group said the number of reporters killed is somewhere between 44 and 100, depending on who does the counting. But Amnesty’s Noor Al-bazzaz said the attacks have threatened the flow of news to the outside world.

Human Rights Watch, based in New York, sent out alerts warning of government crackdowns on reporters in Sudan, its foe South Sudan, and Ethiopia, which imprisons journalists under an anti-terrorism law, including Eskinder Nega Fenta, a journalist and blogger who received the 2012 PEN Freedom to Write Award.

Since South Sudan became independent in July 2011, its security forces have regularly intimidated and unlawfully arrested and detained journalists and editors, HRW said.

Sudan should immediately stop censoring newspapers, HRW said, adding that authorities at the National Telecommunications Corporation also block access to the websites of the opposition online newspaper Hurriyat and the popular forum Sudanese Online.