BEIJING — Warning that China’s arrest of two Canadians has created a dangerous chill for people working on policy and research in that country, more than 100 academics and former diplomats have signed an open letter calling for the two men to be immediately freed.

Made public on Monday, the letter was an international cry of concern from people who work and study in China, saying the arrests threaten the flow of ideas with Chinese academics and officials that is essential for policy work and research aimed at narrowing international rifts.

The letter warned China that the detentions will result in “greater distrust.”

Its signatories included 27 diplomats from seven countries and 116 scholars and academics from 19 countries.

“Meetings and exchanges are the foundation of serious research and diplomacy around the world, including for Chinese scholars and diplomats,” the letter said. The arrests, though, “send a message that this kind of constructive work is unwelcome and even risky in China.”