Canadian businessman Michael Spavor, left, looks on as North Korean leader Kim Jong Un speaks with former U.S. basketball star Dennis Rodman (not in photo) during a visit to North Korea on Jan. 8, 2014. Canada said Spavor has been missing in China since Dec. 10, 2018. (Korean Central News Agency/AFP/Getty Images/file)

A second Canadian has been detained in China on charges of “suspected involvement in activities that jeopardize China’s national security,” increasing fears that Beijing is taking hostages in retaliation for the arrest in Vancouver of a top Chinese business executive.

China’s Foreign Ministry confirmed that both Michael Kovrig, an analyst for the International Crisis Group, and Michael Spavor, who runs cultural exchanges with North Korea, were detained on Monday on “suspicion of engaging in activities that endanger national security.”

Both men worked for nongovernmental organizations and appear to have been picked up for violating China’s strict new rules aimed at controlling the work that foreign NGOs do in China, part of a broader crackdown on civil society and freedom of expression.

Canada’s foreign minister declined to draw a line between the men’s detention and the court battle going on over whether to grant bail to Meng Wanzhou, the chief financial officer at Huawei Technologies who was arrested for extradition to the United States.

But analysts say that it is becoming increasingly apparent that these are acts of reprisal. In a video published Thursday, Hu Xijin, editor of the nationalist Global Times newspaper, warned in English that China’s revenge against Canada “will be far worse than detaining a Canadian.”

Chrystia Freeland, Canada’s foreign minister, said that “Canada is deeply concerned” and had raised the cases directly with Chinese officials.

The Canadian government is advising its embassy staff in China to take extra precautions and has asked China to step up security outside the country’s embassy in Beijing, government officials told reporters. So far, Ottawa has not changed its travel advice for Canadians visiting China.

The diplomatic row was sparked by the arrest of Meng, the daughter of Huawei’s founder, in Vancouver on Dec. 1. She is wanted in New York to face fraud charges related to allegedly breaching American sanctions against Iran.

After a three-day bail hearing, Meng was released Tuesday on $7.4 million bail in Vancouver. She is required to wear an electronic ankle monitor and will be under surveillance 24 hours a day.

The case has opened a new front in the trade war between China and the United States, but Beijing, apparently eager to reach an agreement with the Trump administration, has directed its anger at Ottawa rather than Washington.

China is incensed that Meng could still face extradition to the United States and is threatening “severe consequences” for Canada if Meng is not released.

Under the extradition treaty between Canada and the United States, U.S. officials have 60 days from the date of Meng’s arrest to make a full extradition request. Canada will then have 30 days to determine whether to commence the extradition process. 

More than 90 percent of extradition requests from the United States are granted, according to Canadian government figures.

Both Spavor and Kovrig are being investigated by the local branches of the state security apparatus, rather than the regular police, underlining the severity of the situation. In both cases, local media reported that they were being held “on suspicion of endangering China’s national security.” Chinese authorities have not confirmed the reports.

Spavor was arrested in the northern city of Dandong, where he lives and operates Paektu Cultural Exchange, an organization promoting sporting, business and cultural exchanges with North Korea. He was involved in arranging former U.S. basketball star Dennis Rodman’s first trip to North Korea, and met the leader Kim Jong Un at that time.

More recently, he has been trying to promote business investment in North Korea as the diplomatic environment has become more favorable.

Spavor was due to arrive in Seoul on Monday to speak at a conference about North Korea on Tuesday night. “I’ll be in Seoul from Monday the 10th for a few days for new consulting work,” he wrote on Twitter on Monday.

But he never arrived at his destination, the website NKNews reported, citing multiple people familiar with his itinerary.

Kovrig, a former Canadian diplomat who works on China, Japan and the Korean Peninsula for the Crisis Group think tank, was arrested in Beijing on Monday. 

A Chinese foreign ministry spokesman said that the Crisis Group was not legally registered with the Chinese authorities, suggesting that this meant Kovrig was violating Chinese laws. “The relevant organization has violated Chinese laws because the relevant organization is not registered in China,” spokesman Lu Kang said at a news briefing Wednesday.

A senior Canadian government official said, before news of Spavor’s detention, that Canada has not been provided consular access to ­Kovrig and does not know his whereabouts.

The International Crisis Group also said Wednesday that it had not been able to get in touch with Kovrig. The group called for his immediate release.

Paektu Cultural Exchange, Spavor’s group, also identified itself as an international nongovernmental organization. But it is not clear it if it is registered with the Chinese government or if this is the reason Spavor appears to have been detained.

China has sharply tightened its rules on nongovernmental organizations operating in the country, part of a broader crackdown on civil society and free speech.

Under a law that went into effect at the beginning of 2017, foreign NGOs were brought under the supervision of the Public Security Bureau, rather than the Ministry of Civil Affairs, which had traditionally managed them. This was ostensibly to stop them from undermining state security — which could be anything deemed a threat to the ruling Communist Party.

NGOs are now subject to spot checks by police and strict supervision of their activities and budgets, and they face the constant threat of being closed.

Civic groups, Western governments and business lobbies decried the new rules, saying they would stifle freedom of expression.

There is a precedent for Canadians being held in retribution for the treatment of a Chinese national.

In 2014, Chinese authorities detained a Canadian couple who had lived in China for 28 years. They were Christian aid workers and operated a cafe in Dandong, on the border with North Korea. 

They were arrested after Canada detained a Chinese man wanted for extradition to the United States in a case of industrial espionage. The woman, Julia Garrett, was detained for six months, but her husband, Kevin Garrett, was held for two years.

Coletta reported from Toronto. Yang Liu in Beijing contributed to this report.