Canada is working "very actively" to bring home two of its citizens charged with spying in China, Canadian Prime Minister Justin Trudeau has said.
Michael Kovrig and Michael Spavor were detained in China in December 2018 but were only charged on Friday.
Their arrests came just days after Meng Wanzhou - an executive of the Chinese giant Huawei - was detained in Vancouver, at the request of the US.
China denies that the arrests were in retaliation for Ms Meng's detention.
Mr Trudeau said he was "concerned and disappointed" by the charges against Mr Kovrig, a former diplomat, and Mr Spavor, a businessman, calling their detention "arbitrary".
Canadian officials were using both private and public tactics "to make sure we have a positive outcome", he added at a press conference on Friday.
Mr Kovrig and Mr Spavor have been charged with "spying on national secrets" and providing intelligence for "outside entities".
Canada's Deputy Prime Minister Chrystia Freeland said she was "heartbroken and really angry" when she heard the pair had been charged, adding that Canada "will not rest" until they come home.
The men are "very brave Canadians who are behaving with incredible decency and incredible courage" and are in very difficult circumstances "through no fault of their own", she said.
China's court system is completely controlled by the Communist Party and has an almost 100% conviction rate once defendants are charged, notes the BBC's Stephen McDonell in Beijing.
The Chinese government has not explicitly linked the cases of the two Canadians with Meng Wanzhou but it has dropped heavy hints that there is a connection, he explains.
At the Chinese foreign ministry's regular press briefings, spokespeople routinely mention the fate of the Canadians and that of the daughter of Huawei's founder in the same response.
Mr Kovrig and Mr Spavor could face 10 years in prison if found guilty of violating Article 111 of the Criminal Law of the People's Republic of China.
The Canadian prime minister also said he continued to highlight to China that the Canadian judicial system is independent and Mr Trudeau's government cannot interfere with their decisions about Ms Meng.
Canada's concern for "the Two Michaels"
Jessica Murphy, BBC News, Toronto
In Canada, Michael Spavor and Michael Kovrig are now frequently referred to simply as "the Two Michaels".
It's an indication of how closely followed their detention has been in Canada.
They are undoubtedly the most high-profile Canadian citizens being held abroad. Their cases are raised by Canadian officials and in the media almost every time Meng Wanzhou's trial makes news.
Prime Minister Justin Trudeau has become increasingly blunt about their cases as months pass, now openly suggesting their arrest was a tit-for-tat reaction by Beijing to Canada's arrest of Ms Meng.
Since their detention, Canada has pressed many of its allies to speak in support of Mr Spavor and Mr Kovrig, including Australia, France, Germany, Spain, the UK, the US, the EU, and the G7.
News they have been charged comes amid an ongoing deterioration in how Canadians view China.
Polls suggest Canadians are increasingly concerned about human rights in that country and sceptical about any potential Huawei involvement in Canada's 5G network.
What is the timeline?
Meng Wanzhou - the chief financial officer of Huawei, and daughter of the company's founder - was arrested on 1 December 2018 in Vancouver.
Her arrest was requested by the US, which accuses her of breaking Iranian sanctions. She is still fighting extradition to the US.
On 10 December, the Canadians were detained in China. They were formally arrested in May 2019 and charged 13 and a half months later.
In September, Mr Trudeau accused China of "using arbitrary detention as a tool to achieve political goals".
How have they been treated?
Michael Kovrig's employer, the Crisis Group think tank, says on its website that he has not seen a lawyer or his family since the detention, and that he only has "periodic consular visits".
"Michael's work has included meeting... Chinese officials, academics and analysts from multiple Chinese state institutions," the Crisis Group said.
"He has attended numerous conferences at the invitation of Chinese organisations. He frequently appears on Chinese television and in other media to comment on regional issues.
"Nothing Michael does has harmed China."
The Free Michael Spavor website, updated earlier this year, said he was "behind bars, without his family, and without access to lawyers".
"Michael is an earnest, genuine, and impossibly fun person, who we believe has been detained in error," the website says.
In April 2019, it was reported that both men were being interrogated for between six to eight hours a day, and were sometimes subject to 24-hour artificial lighting.
The Chinese government says the men are in "good health".
What is the latest with Meng Wanzhou?
Last month, a Canadian court ruled that her case could go forward.
A judge found the case met the threshold of double criminality - meaning the charges would be crimes in both the US and Canada.
Her lead defence lawyer, Richard Peck, argued that Canada was effectively being asked "to enforce US sanctions".
A year after her arrest, Ms Meng released an open letter, detailing her life in detention at her home in Vancouver.
"Over the past year, I have learned to face up to and accept my situation," she said. "I'm no longer afraid of the unknown."
She also said she finally had time to "read a book cover to cover," or "carefully complete an oil painting".