WASHINGTON (AP) — Journalist Shohret Hoshur left China 20 years ago, fearing for his safety after authorities branded him a separatist for his critical coverage of the plight of his fellow ethnic Uighurs. Now based in Washington, Hoshur says Chinese authorities have adopted another tactic to get him off the airwaves — pressuring his family.

The State Department on Thursday voiced deep concern over reports that three of Hoshur's brothers in his native land have been imprisoned in retribution for his journalism. The 49-year-old reporter says it follows years of threats by authorities in the restive region of Xinjiang in China's far west, where his broadcasts in the Uighur language offer a rare alternative to state-run media.

There's been no coverage of their cases in Chinese media, but his relatives in Xinjiang have been told by police that one brother was sentenced to five years at a mass trial in June, accused of endangering state security. The other two were detained in August, apparently for "leaking state secrets" after speaking by phone to Hoshur about the trial. They haven't been seen by their family since.

"We urge Chinese authorities to cease harassment of his family and to treat them fairly and with dignity," State Department spokeswoman Jen Psaki told a press briefing in Washington, urging respect for internationally-recognized human rights, including freedom of expression.

China's embassy in Washington did not immediately respond to a request for comment.

Hoshur reports for U.S. government-funded Radio Free Asia. He told The Associated Press that authorities began harassing his family in Xinjiang's Qorghas county after a September 2009 story about the death of a Uighur torture victim. The pressure intensified last spring as authorities cracked down on perceived enemies among Uighurs — a Muslim minority group in China — amid a series of deadly attacks over recent months that Chinese authorities have blamed on radical separatists.

Hoshur said his brothers are farmers and merchants with little if any interest in politics or social issues, and dismisses the validity of any of the charges brought against them. He also said he won't give into pressure to give up his journalism with Radio Free Asia, although his sister-in-law has been told by local government officials that's the only way to get his brothers released.

"In my personal experience, the Chinese authorities could intensify their pressure after you start obeying them," said Hoshur who has been honored at the New York Festivals radio program awards for his investigative coverage of Uighurs who have gone missing since deadly unrest in Xinjiang in 2009.

"If I leave from my job, this method can be used widely among Uighurs abroad as a successful tactic. I don't want to be made an example of, obeying an authoritarian regime's unacceptable demand," he said.

The Committee to Protect Journalists drew attention to the plight of Hoshur's brothers on Wednesday, describing it as a "long-distance tactic to suppress Uighur coverage."

The New York-based group says China was the world's worst jailer of journalists in 2014, with 44 in jail, up from 32 in 2013.