While McDougall did not cite her sources, the numbers of people forced into detention and into re-education matched a report that the Network of Chinese Human Rights Defenders submitted to the committee.
A Chinese official told a United Nations human rights committee in Geneva that tough security measures in China's far-west Xinjiang region were necessary to combat extremism and terrorism, but that they did not target any specific ethnic group or restrict religious freedoms.
Information in Xinjiang is tightly controlled - the province was cut off entirely from the internet for 10 months in 2009 and is still subject to greater censorship and surveillance than other parts of China.
"The turnaround in Xinjiang's security situation has avoided a great tragedy and saved countless lives, thanks to powerful Chinese law and the strong ruling power of the Communist Party of China", the paper wrote.
In an editorial with the headline "Safeguarding Xinjiang's peace and stability is the most important human right", the Global Times said: "There is no doubt that intense control contributes to Xinjiang's peace today. Maintaining peace and stability in the region is the core interest of people both in Xinjiang and all of China", it states.More news: Boy among 26 dead as bridge collapses in Genoa
The country responded to concerns, raised by a member of a United Nations human rights committee, that its Xinjiang region has been turned into "something resembling a massive internment camp, shrouded in secrecy, a sort of no-rights zone".
McDougall expressed concerns the Uighurs were being treated "as enemies of the state exclusively on the basis of their ethnoreligious identity".
Beijing has long denied the existence of such camps, and has made no comment on the latest allegations.
"There are estimates that upwards of a million people are being held in so-called counter-extremism centres", she said.
She said over a hundred Uighur students, who returned to Xinjiang province from overseas, had disappeared, while others were either detained or died in detention.More news: Asian stock markets recover from the escalating financial crisis in Turkey
Chinese officials have said tightened security measures and limits on the religious practices of Uighurs, who are mostly Sunni Muslim, are aimed at trying to prevent violent, anti-state episodes in Uighur areas, which they have attributed to separatism, terrorism and religious extremism.
Some Uighurs found their way into the ranks of Islamist militias in Syria and Iraq, believing by obtaining military training and global jihadist solidarity, they would be able to one day take the fight back to Xinjiang. "But the Chinese government just closes its eyes", he told Reuters.
"Detentions are extra-legal, with no legal representation allowed throughout the process of arrest and incarceration", the submission said, adding there were "widespread" reports of torture.
Earlier this year, the foreign ministry declared that concerns about the mistreatment of the Uighurs were "unjustified" and criticism amounted to "interference in China's internal affairs", The Guardian reports.More news: Trump campaign files arbitration complaint against Omarosa