(CNN) -- Foreign journalists working in China have faced a number of "negative trends" over the past year, according to the Foreign Correspondents' Club of China.
Several journalists from U.S. news organizations Bloomberg and the New York Times faced unexplained delays in renewing their press cards and visas after publishing controversial stories.
Here's a timeline of the key moments leading up to the visa row:
May 8, 2012
Al Jazeera is forced to close its English-language bureau in China and is refused a visa renewal for correspondent Melissa Chan. Though Chinese officials didn't elaborate on the reasons, observers believe it was due to the network's decision to run a documentary about China's controversial "re-education through labor" camps.
June 29, 2012
Bloomberg publishes piece about the expanding business interests of Chinese President Xi Jinping's extended family as he rose to power. Bloomberg's website is later blocked in China.
October 25, 2012
New York Times, citing corporate and regulatory records, reports that family members of then Premier Wen Jiabao had amassed a fortune worth billions of dollars.
October 26, 2012
China blocks New York Times website after story on Wen Jiabao's family wealth.
December 31, 2012
New York Times correspondent Chris Buckley is forced to leave China after he was refused a visa. He had rejoined the Times after moving from Reuters. The authorities suggested his application was filed incorrectly.
November 8, 2013
New York Times publishes piece suggesting that Bloomberg had taken a decision to curb stories liable to cause anger in China.
November 9, 2013
Veteran journalist Paul Mooney is denied a visa to work in China in a new position with Reuters. He is not given a reason.
November 13, 2013
New York Times runs a piece linking JPMorgan Chase to an obscure consulting firm in China run by 32-year-old Lily Chang -- the alias for "Wen Ruchun," the daughter of Wen Jiabao.
December 5, 2013
U.S. President Joe Biden criticizes China's treatment of U.S. journalists and highlights the lack of press freedom in China as he meets U.S. reporters in Beijing.
December 9, 2013
In its year-end statement, the Foreign Correspondents' Club of China said that Chinese authorities were increasingly using the denial of visas, or delays in their approval, in an apparent effort to influence journalists' coverage. It said that no correspondents for the New York Times and Bloomberg had been able to renew their annual residence visas, which had been subject to unusual and unexplained delays.
December 19, 2013
Bloomberg reporters and some New York Times reporters are issued press cards. New York Times spokesperson tells CNN company is hopeful that its resident journalists will be issued visas that will allow them to continue to work in the country.