Chinese President Xi Jinping Reuters By now, it is well known that China regularly seeks to silence its critics at home.

But what happens when those critics are Chinese nationals who live abroad and enjoy the legal protections of the United States or Europe?

Increasingly, the Chinese Communist Party is trying to muzzle those dissidents by intimidating family members at home.

Over the last week, two exiles living in Germany and New York have accused authorities here of “abducting” relatives in China to exert pressure on them.

These latest detentions appear related to the online publication last week of an anonymous letter criticizing Chinese President Xi Jinping and calling for him to resign. Chinese police seem intent on discovering who authored and distributed the letter, wherever they are located.

“This is something we have been seeing more and more in the last few years,” said William Nee, China researcher for Amnesty International in Hong Kong. Family members in China, he argues, are becoming pawns in efforts by state security to mute criticism abroad.

Wen Yunchao, a prolific blogger and Chinese exile living in New York, said he learned last week that police in southern China had detained his 72-year-old father and 65-year old mother, along with his brother, on March 22.

Mr. Wen says he had nothing to do with writing the Xi letter. But he did share a link to the letter on his Twitter account, which may have put him on the radar of Chinese security.

Worried about parents

View through the fence of a prison in China. AP Wen said in an email to the Monitor that he has yet to learn about his family’s whereabouts or their condition. “I am worried that my elderly parents cannot bear it emotionally or physically,” he wrote.

On Sunday, a Chinese journalist living in Germany reported that authorities had detained his two brothers and a sister in Sichuan Province. The journalist, Chang Ping, said that Chinese authorities issued an ultimatum - dispatched via one of his brothers - on what Chang must do to free his family members.

According to Mr. Chang, the authorities want him to disavow and take down a commentary he recently published in Chinese on the website of Deutsche Welle, a German broadcaster. The commentary criticized government authorities for the “secret kidnapping” of a Chinese journalist, Jia Jia, as part of their probe into the anonymous letter.

In an email, Chang said he’s concerned for the safety of his family, but would not stay silent, much less ask Deutsche Welle to take down his commentary.

“DW will not withdraw an article just because police in China demand it,” Chang wrote Monday in a statement posted on China Change, a US website focused on human rights in China. “This is an utterly ridiculous and rude demand.”

Bill Bishop, a China expert based in Washington DC, said he’s been surprised by the harsh Chinese response to the Xi letter. “The reaction of the security service has turned this into an international story,” said Bishop, who writes the influential Sinocism China Newsletter.

The dissenting letter has gripped the party's attention partly because of its uncertain origins. Was it written by a party member or an outsider? Then there's the letter's timing: It appeared briefly on Wu Jie News, a Chinese web site, right before the start of China’s legislative session in early March, a sensitive time here.

Censors quickly took down the letter and detained employees of Wu Jie News, but by then it had been shared widely inside and outside of China.

'Cult of personality'?

Amnesty International volunteers tie cloth gags across their mouths during a protest in central Sydney in 2008. They demonstrated against what they claim is the Chinese government's censorship, monitoring and surveillance of internet users in China. REUTERS/Will Burgess The letter, which claims to be written by “loyal Communist Party members,”has a point-by-point critique of Xi’s rule, including his consolidation of power and the “cult of personality” the letter alleges he has created.

"Comrade Xi Jinping, we feel that you do not possess the capabilities to lead the Party and the nation into the future, and we believe that you are no longer suitable for the post of General Secretary," the letter reads.

Some Sinologists have said the letter was written in the style of party members; Bishop said it was difficult to tell. While disgruntled cadre have distributed such letters during past internal power struggles, said Bishop, there have also been instances of “overseas groups” distributing bogus documents to create the appearance of dissent in the party.

Bishop also noted that exiled Chinese activists have long had to weigh if their actions abroad could have repercussions for their families. Following the 1989 crackdown on Tiananmen Square protestors, hundreds of student activists fled to Taiwan, the US, and other countries. Some have been told by Chinese authorities that they can only return to visit family if they abandon their anti-PRC activism.

Over the last two years, Chinese authorities appear to be upping the pressure on exiles abroad, particularly journalists. In August of 2014, police in far western Xinjiang province detained and arrested two brothers of Shohret Hoshur, a reporter for Radio Free Asia based in Washington. As a reporter, Mr. Hoshur has broken numerous stories about ethnic violence in Xinjiang, his former home.

The arrests of his brothers were widely seen as retaliation for this reporting. While authorities ended up releasing the two brothers late last year, a third brother, Tudaxun Hoshur, remains in prison, serving a five-year sentence for endangering state security.

In the most recent cases, both Wen Yunchao and Chang Ping say they have been told that family members could face further repercussions if they don’t change their ways. Media rights groups are rallying to their defense.

“Detaining family members of independent journalists living outside China is nothing but blackmail,” said Robert Mahoney, deputy executive director of the Committee to Protect Journalists, in a statement. “China is clearly resorting to such tactics at home to intimidate critics abroad.”

Hong Kong booksellers

In this Aug. 22, 2015 file photo, Chinese female troops practice marching near a billboard showing Chinese President Xi Jinping and the slogan "Strive to build a People's Liberation Army that obeys the Party, Wins the war and has outstanding work style“ at a camp on the outskirts of Beijing. AP China also appears to be testing its clout in getting objectionable material removed from foreign websites and Hong Kong publishing houses. Late in 2015, Chinese authorities pressed a Beijing-based foreign correspondent, Ursula Gauthier, to renounce and take down an article she had written for a French publication about violence in Xinjiang. When she refused, authorities refused to renew her media accreditation, forcing her to leave China.

Also late last year, five Hong Kong booksellers disappeared from the former British colony and were later found to have been detained by police on the Chinese mainland. Three of them since have returned to Hong Kong, with at least one, British citizen Leo Po, vowing to stop publishing books the Communist Party finds objectionable.

Mr. Nee, the Amnesty researcher, said that such retaliation is only harming China’s international image, particularly when innocent family members are targeted. “It is backfiring,” he said, adding that foreign diplomats should push this view when meeting with their Chinese counterparts.

“Foreign governments need to make clear that this behavior is absolutely unacceptable,” said Nee. “Detaining and harassing people who done nothing but give their opinion on overseas web sites is completely against international standards.”