On Monday, Canada's foreign minister, Chrystia Freeland, said her government - which has come under fire previously for signing off on the sale of more than 900 armoured vehicles to Riyadh - would continue to call for the release of the detained activists. It stopped medical treatment of Saudis in Canada and made arrangements to bring home Saudi patients.
"The matter is not about human rights; it is a matter of national security", the minister said.
Saudi Arabia, one the world's top executioners, beheaded 48 people in the first four months of 2018, according to Human Rights Watch - but crucifixions are rare.
When asked about the jailed activists, Jubeir reiterated the government's earlier stance that they had been in contact with foreign entities, but did not specify the charges against them.
Since then, the Saudi kingdom has pursued a scorched-earth policy towards anything related to Canada.
The Saudi Foreign Ministry took exception to the wording of the tweet, calling it an attempt by Canada to interfere with the country's internal affairs.
Saudi Arabia's main state wheat buying agency, the Saudi Grains Organization, has also told grains exporters it will no longer accept Canadian-origin grains in its worldwide purchase tenders, according to European traders.
"I will say Canada is very comfortable with our position", she told reporters.
Since rising to power in 2015, Crown Prince Mohammed bin Salman has courted Western allies to support his reform plans, offering billions of dollars of arms sales and promising to fight radicalism in the kingdom.
Canada imported 71,300 barrels of crude a day from Saudi Arabia as of 2014, accounting for about 11 percent of the country's imports, according to Natural Resources Canada.
The kingdom has suspended educational exchanges with Canada and moved Saudi scholars to other countries.
Canada's Prime Minister Justin Trudeau is expected to hold a news conference in Montreal.
The dispute may hurt what is a modest bilateral trade worth almost $4 billion a year. Saudi Arabia has invested about $6 billion in Canadian businesses since 2006, data compiled by Bloomberg show.