The daughter of missing human rights activist Dong Guangping from China, who vanished last summer after being arrested in Vietnam, is speaking out about Vietnam鈥檚 lack of response to UN and Canadian officials about his whereabouts.

鈥淭he government of Vietnam continues to torment my family, by refusing to explain why they arrested my father almost six months ago, and what has happened to him since,鈥 said Katherine Dong, a Toronto university student and Canadian citizen who says she has not heard from her father in months.

鈥淚 had hoped he would be safely reunited with us here in Canada by now, instead we are left to agonize about his safety. We don鈥檛 even know where he is. [Vietnam] won鈥檛 answer my questions,鈥 she said in a press release Tuesday.

Dong, 64, is an activist known for condemning China鈥檚 efforts to censor information about the state鈥檚 massacre of protesting students in Tiananmen Square in 1989.

He was arrested on Aug. 22 in Hanoi, the capital of Vietnam, where he had travelled after fleeing China in January 2020. Dong had been granted asylum in Canada, where his family was able to resettle in 2015鈥 but Ottawa had not been able to convince Vietnamese officials to let him leave the country.

In December, three UN human rights officials sent communications to Vietnam, saying they are 鈥渟eriously concerned鈥 about what appears to be the 鈥渁rbitrary detention, enforced disappearance and risk of refoulement鈥 of Dong.

According to their communications, Dong was last seen handcuffed and blindfolded, entering a police car and being escorted by dozens of police officers outside his apartment.

Dong is at imminent risk of persecution if Vietnamese authorities decide to send him to China and no one, including his family and legal representatives, have received accurate information about where he is, the officials state.

The letter states that if the allegations against Vietnam are true, it would be in violation of human rights treaties, including the Convention against Torture and other Cruel, Inhuman or Degrading Treatment.

The UN officials urged Vietnam to tell them where Dong is, the legal grounds for detaining him, how their actions are compatible with Vietnam鈥檚 international obligations to human rights and how human rights defenders are protected in Vietnam, among other demands.

They provided Vietnam with 60 days to respondbut as of Tuesday, the country鈥檚 officials missed the deadline. The UN made its letter public as a result.

Advocates told CTV National News in November that the family has been informed the case wasraised by Prime Minister Justin Trudeau and Foreign Affairs Minister Melanie Joly in meetings at last year鈥檚 G20 summit in Indonesia and with leaders of Southeast Asian countries in Cambodia.

Global Affairs Canada also told CTV National News in November it is 鈥渄eeply worried about Mr. Dong鈥檚 safety and wellbeing and has been raising our concerns at the highest levels. Officials are working to ascertain his whereabouts, including through diplomatic engagement with both Vietnam and China.鈥

Katherine Dong said in the press release Tuesday that Vietnam 鈥渨on鈥檛 answer questions posed by the Prime Minister and the Minister of Foreign Affairs of Canada. Now they refuse to answer the United Nations.鈥

鈥淭his is unacceptable and an affront to international law. Vietnamese officials must answer our simple question, 鈥榳here is Dong Guangping?鈥欌 she said.

Prior to his detainment in Vietnam, Dong had been criminally prosecuted in China three times for his work in support of human rights and democracy, advocating for peaceful assembly to commemorate the events in Tiananmen Square in 1989, according to the UN.

With files from CTV National News, Ottawa Correspondent, Judy Trinh