The Foreign Correspondents' Club of China said on Wednesday that the foreign ministry had "effectively" ejected BuzzFeed News's Beijing bureau chief from the country after declining to renew her visa.
Megha Rajagopalan, who is American and had been in China for six years, said on Twitter that the foreign ministry had "declined to issue me a new journalist visa" in May.
"They say this is a process thing, we are not totally clear why," wrote Rajagopalan, who left the country in late February.
Rajagopalan has reported extensively on China's security crackdown in the far-west region of Xinjiang, where rights groups say hundreds of thousands of mostly Muslim ethnic Uighurs are held in re-education camps.
The Foreign Correspondents' Club of China said in a statement that she had "conducted herself according to the highest journalistic standards while in China".
The foreign ministry "declined to give a clear and transparent reason for denying her a visa", it said.
"We find this extremely regrettable and unacceptable for a government that repeatedly insists it welcomes foreign media to cover the country," the statement said.
The FCCC, of which Rajagopalan is a former board member, said it was seeking clarity from the foreign ministry "on its reasoning for effectively ejecting a credentialed foreign journalist from China".
The foreign ministry said in a brief statement to AFP: "The Chinese government handles foreign journalists' visas for China in accordance with laws and regulations."
It is not the first time that a foreign journalist has been denied a new visa.
Al-Jazeera reporter Melissa Chan had to leave China in 2012 after authorities refused to renew her visa.
In 2016 French reporter Ursula Gauthier was forced to leave the country after she criticised government policy in Xinjiang and the authorities refused to renew her credentials.
"It is bittersweet to leave Beijing after spending six wonderful and eye-opening years as a journalist there," Rajagopalan wrote on Twitter, adding that she would continue reporting on Xinjiang from her new BuzzFeed post covering technology and human rights from the Middle East and beyond.