The man Justin Trudeau put in charge of repairing Canada’s ties with China acknowledged he has his work cut out for him.

Dominic Barton, who the prime minister tapped as ambassador to Beijing in September, said Canada’s arrest of a top Huawei Technologies Co. executive in late 2018 “fundamentally changed” the nation’s relationship with its second-largest trading partner.

“The chill is real,” Barton told lawmakers Wednesday evening in Ottawa. He added that helping secure the release of the two Canadians locked up in China in the days that followed Meng Wanzhou’s detention is his top priority.

Barton, the former global head of McKinsey & Co. Inc., said he is “consistently and constructively” pressing Chinese officials about the two men, who Canada argues have been imprisoned arbitrarily. He is also seeking clemency for a third Canadian who was sentenced to death in a drug case.

His testimony comes as Canada negotiates the evacuation of its citizens from the Chinese epicenter of a deadly coronavirus outbreak. A charter flight planned for Thursday has been delayed by weather but is expected to leave Wuhan soon, Barton said.

Promoting human rights is second on Barton’s priority list, and he said he’s heard first-hand accounts of an increased crackdown on dissent by China over the past year. In particular, he highlighted “credible reports of the mass detention, repressive surveillance and family separation” of Uighur and other Muslims in Xinjiang province and said he would urge Chinese officials to end the practice and release all those detained.