U.K. Foreign Secretary Dominic Raab said the country is deeply concerned over China’s charges against Michael Kovrig and Michael Spavor, according to a post on Twitter.

“The U.K. and Canada share a commitment to uphold the rule of law and oppose arbitrary detention,” he wrote in a retweet of a statement from Francois-Philippe Champagne, Canada’s Minister of Foreign Affairs.

Chinese authorities indicted the two Canadians on spying allegations in a case diplomatically entwined with U.S. efforts to extradite Meng Wanzhou, a top Huawei Technologies Co. executive from Canada.

Kovrig is an analyst with International Crisis Group based in Hong Kong, while Spavor is a former Canadian diplomat. They’ve been held in detention for 18 months.