Hong Kong (CNN) United Nations counter terrorism chief Vladimir Ivanovich Voronkov has come under heavy criticism from the United States and human rights groups over his recent trip to China's repressive Xinjiang region.

Voronkov finished a three-day trip to the region on June 15, and issued a statement in which he said he met with local officials in Urumqi and "briefed on the implementation of the UN Global Counter-Terrorism Strategy."

There was no mention in Voronkov's press release of the estimated two million Muslim majority Uyghur who, according to the US State Department , have been held in mass detention centers in the far western region.

UN Secretary General Antonio Guterres raised the issue of Xinjiang with President Xi Jinping during a trip to China in April though the details of their conversation weren't made public.

Quoting a statement from China's foreign ministry, state media reported that local officials and Voronkov had reached a "broad consensus" during his trip, suggesting the UN was supportive of its counter-terrorism efforts.

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