A group of former ambassadors and academics is calling on China to immediately release two Canadians it detained in the wake of the arrest of a top Huawei Technologies Co. executive in Vancouver.

The open letter, dated Monday and addressed to Chinese President Xi Jinping, says its 141 signatories are “deeply concerned” by the detentions of Michael Kovrig and Michael Spavor by state security officials. Kovrig is on leave from a job in Canada’s foreign service, and was working for the International Crisis Group when detained, while Spavor ran outreach tours in North Korea.

The detentions “send a message that this kind of constructive work is unwelcome and even risky in China,” the group says in the letter. “We who share Kovrig and Spavor’s enthusiasm for building genuine, productive, and lasting relationships must now be more cautious about traveling and working in China and engaging our Chinese counterparts.”

The letter was signed by dozens of scholars and former envoys, including former ambassadors to China from Canada, the U.S., the U.K., Mexico, Germany and Sweden.

Tensions created by China’s move “will lead to less dialogue and greater distrust, and undermine efforts to manage disagreements and identify common ground. Both China and the rest of the world will be worse off as a result,” the envoys say.

Huawei Arrest

The letter comes as Prime Minister Justin Trudeau urges other world leaders to speak out against Beijing’s actions in the aftermath of the arrest last month of Huawei Chief Financial Officer Meng Wanzhou in Vancouver. She now faces extradition to the U.S., where she is wanted in connection with alleged Iran sanctions violations. China captured Kovrig and Spavor nine days later, and has since sentenced a third Canadian man to death on a drug charge.

Meng is out on bail, while the Canadians remain in Chinese custody, being questioned for up to four hours daily.

As Trudeau presses for their release, his government is weighing whether to restrict or ban Huawei from its 5G networks. “We will make the decision that’s in Canada’s best interest and we will not compromise security,” Public Safety Minister Ralph Goodale told reporters in Ottawa on Monday.

China’s ambassador to Ottawa, Lu Shaye, warned last week there would be repercussions if Canada doesn’t make a “wise decision” on ultra-fast, next-generation wireless technology. On Monday, however, Chinese Foreign Ministry Spokeswoman Hua Chunying said Lu “did not mean that China intends to interfere in the decision-making of the Canadian government,” according to a Chinese transcript of the daily press briefing.

“We all know that Huawei is a leading supplier in the 5G technology, so losses are inevitable if Huawei is not chosen as a cooperation partner,” she said.