The Canadian government is treating the disappearance of a woman from Quebec and her Italian friend in Burkina Faso as a kidnapping, media reports say.
Edith Blais, 34, and Luca Tacchetto, 30, were last heard from on 15 December in the city of Bobo-Dioulasso.
The pair were travelling in Western Africa and were making their way to Togo for a humanitarian project.
Canada has travel advisories for Burkina Faso, due to terrorism and kidnapping.
"We're really worried because… the communications stopped abruptly and every kind of activity, every trace just completely vanished," Ms Blais' sister, Melanie Blais, told CTV News.
"They weren't worried about anything. They were having a really happy trip. She has been dreaming about travelling to Africa for all of her life."
A Facebook group set up by friends and family of Ms Blais says the couple were heading to Ouagadougou to sell their car, but never made it to the Togo border crossing or applied for visas.
The Canadian government has a travel advisory warning against all travel in Burkina Faso along the Togo border because of threats of "banditry and terrorism".
Radio-Canada reported that the Canadian government is treating their disappearance as a kidnapping, although the kidnapping has not been confirmed.
Global Affairs Canada told the CBC it is treating Blais's case as "extremely high priority.”
Have your say
More World Headlines
- Trump renews attacks on congresswomen of colour: ‘Let them leave’ America
- Kenya deports 17 foreign directors of betting firms
- Former president of ECOWAS Commission De Souza passes away
- Mexican drug lord El Chapo gets life in prison
- Africans 'twice as likely to be refused a UK visa'
- Tom Steyer: Trump 'has met' criteria for impeachment
- US House votes to condemn Trump's attacks on congresswomen
- Zuma says he received death threat after commission testimony
- I am not a racist - Trump insists
- Turkish sailors held hostage off Nigeria coast
- Shoppers find drug stash in their soap powder box
- Trump tweet row: Don't take the bait, congresswomen say
- WHO on high alert on possible Ebola outbreak
- May condemns Trump's 'go home' remark to congresswomen
- Zuma denies being 'king of corrupt people'