Saudi Arabia and Canada have showed no signs of backing down in an escalating row over human rights, after Riyadh abruptly cut ties over vigorous Canadian calls for the release of activists jailed in the kingdom.
The Saudi government expelled Canada's ambassador, giving him 24 hours to leave the country.
It also recalled its own envoy to Ottawa, while freezing all new trade over what it slammed as "interference" in its internal affairs.
Canada did not give any ground over the expulsion of ambassador Dennis Horak, with Foreign Minister Chrystia Freeland saying Canada would continue to defend human rights around the world.
The incident, which underscores a newly aggressive foreign policy led by Crown Prince Mohammed bin Salman, comes after Canada denounced a new crackdown on women and human rights campaigners in Saudi Arabia.
"The kingdom announces that it is recalling its ambassador to Canada for consultation. We consider the Canadian ambassador to the kingdom persona non grata and order him to leave within the next 24 hours," the Saudi foreign ministry tweeted early yesterday.
The ministry also announced "the freezing of all new trade and investment transactions with Canada while retaining its right to take further action".
Later, the row appeared to escalate as Riyadh said it will relocate thousands of Saudi students studying in Canada to other countries, and state airline Saudia announced it was suspending flights to and from Toronto.
A pro-government Saudi Twitter account provoked outrage when it posted - and then deleted - a 9/11-style digitally altered image showing a plane flying towards the Toronto skyline.
The account later apologised and the image was reposted with the plane removed, but screenshots of the original tweet spread quickly.
Saudi Arabia's media ministry said it was investigating the incident.
Foreign Minister Adel al-Jubeir said Saudi Arabia "will deal with any interference decisively", dismissing Canada's position as "built on misleading information", in a statement carried by state media.
Last week, Canada said it was "gravely concerned" over the new wave of arrests of rights campaigners, including award-winning gender rights activist Samar Badawi, and called on Riyadh to "immediately release them".
"Canada will always stand up for human rights, in Canada and around the world, and women's rights are human rights," Ms Freeland told an audience in Vancouver.
Ms Badawi was arrested along with fellow campaigner Nassima al-Sadah last week, the latest victims of what Human Rights Watch called an "unprecedented government crackdown on the women's rights movement".
Ms Badawi's brother, blogger Raif Badawi, was arrested in 2012 and sentenced to 1,000 lashes and ten years in jail for "insulting Islam" in a case that sparked an international outcry.
The latest arrests come weeks after more than a dozen women's rights campaigners were detained and accused of undermining national security and collaborating with enemies of the state. Some have since been released.
Prince Mohammed, heir to the region's most powerful throne, has introduced a string of reforms such as lifting a decades-long ban on women drivers in a bid to overhaul the kingdom's austere image.
However, the 32-year-old has simultaneously pursued a combative foreign policy, including leading a blockade of neighbouring Qatar and a bombing campaign against Iran-backed Houthi rebels in Yemen, while cracking down on dissent at home.
The United Arab Emirates, a strong regional ally, supported the Saudi response to Canada, with a senior government official calling Canadian behaviour "unacceptable".
In April, Canadian Prime Minister Justin Trudeau expressed his "serious concern" over the continued jailing of Mr Badawi to Saudi King Salman.
Mr Badawi's wife Ensaf Haidar has been granted asylum by Canada, where she is raising their three children.
"It is now time for other governments to join Canada in increasing the pressure on Saudi Arabia to release all prisoners of conscience immediately and unconditionally," said Samah Hadid, Amnesty International's Middle East campaigns director.
However, the singling out of Canada is aimed at strongly discouraging other critical Western governments from speaking out, observers say.
