Beijing: Canadian businessman Michael Spavor, who worked with North Korea, is being investigated on suspicion of harming China’s state security, officials said, days after a former Canadian diplomat was detained in China in an escalating diplomatic row.

The state security bureau in the northeastern Chinese city of Dandong, which borders North Korea, has been investigating Spavor since Dec. 10, an official news site for the Liaoning province government said on Thursday.

It did not give further details.

The announcement follows the detention in Beijing on Monday of former diplomat Michael Kovrig, who works for the International Crisis Group (ICG). State media in China has reported Kovrig is being investigated on the same charges.

China has reacted angrily to Canada’s arrest on Dec. 1 of Chinese executive Meng Wanzhou, the chief financial officer of China’s Huawei Technologies [HWT.UL], and Spavor’s investigation is likely to further escalate the diplomatic row.

Meng’s arrest was made at Washington’s request. She has been accused by U.S. prosecutors of misleading banks about transactions linked to Iran, putting the banks at risk of violating sanctions.

Officials say China had so far not tied Kovrig’s detention to Meng’s arrest, although Canadian diplomatic experts have said they have no doubt the two cases are linked.

Canada has been unable to contact Spavor since he notified the government that he was being questioned by Chinese authorities, Foreign Ministry spokesman Guillaume Bérubé said in statement issued in Canada late on Wednesday.

Canadian officials were working hard to ascertain Spavor’s whereabouts and would continue to raise the issue with the Chinese government, Bérubé said.