Canadians Michael Kovrig, a former diplomat, and Michael Spavor, a businessman who organized trips to North Korea, have been formally arrested in China on spy-related charges, Reuters reports. The men have been detained without charge since December, but on Thursday China’s foreign ministry announced both had now been formally arrested. According to spokesman Lu Kang, Kovrig is accused of gathering state secrets and Spavor is accused of stealing secrets for overseas forces. Both men deny being spies. The arrests are thought by Canadians to be in retaliation for the arrest of Huawei executive Meng Wanzhou last year on a U.S. extradition order in connection with violating Iran sanctions.