Supporters of Michael Kovrig and Michael Spavor march to mark 1,000 days since the Canadians were arrested in China, during a protest in Ottawa, Ontario, Canada September 5, 2021. REUTERS/Blair Gable Reuters (Reuters) - Supporters of two Canadians accused of spying and held in Chinese prison for 1,000 days rallied on Sunday, demanding their release in a case that has soured diplomatic ties between Ottawa and Beijing. Businessman Michael Spavor and former diplomat Michael Kovrig were detained in December 2018, shortly after Canada arrested Meng Wanzhou, the chief financial officer of Huawei Technologies on a warrant from the United States....