Canadian Foreign Minister Chrystia Freeland on Wednesday warned the United States not to politicize extradition cases, a day after President Donald Trump said he could intervene in the affair of a Chinese executive detained in Canada at Washington’s request.

Freeland also told reporters that a second Canadian citizen could be in trouble in China. Authorities in China are already holding former diplomat Michael Kovrig, who was detained on Monday.

Officials say China had so far not linked Kovrig’s detention to the arrest in Vancouver on Dec. 1 of Huawei Technologies Co Ltd Chief Financial Officer Meng Wanzhou, which infuriated Beijing. But Canadian diplomatic experts have said they have no doubt the two cases are linked.

US prosecutors accuse Meng of misleading multinational banks about Iran-linked transactions, putting the banks at risk of violating US sanctions. She has said she is innocent.