Obama voiced support for Trudeau ahead of the general election next week in the context of challenging Canadian Prime Minister.

"I'm proud to be working with Justin Trudeau as president," Barack Obama wrote on Twitter on October 16. "He is a hard-working, effective leader who deals with big issues like climate change. The world today needs his radical leadership. I hope their northern neighbors." I support him for another term. "

"Thank you, my friend. We are working hard to keep making progress," Canadian Prime Minister Justin Trudeau responded.

The close friendship between Obama and Trudeau has become a popular topic on social media since the 44th US president was discharged. They had dinner together at a restaurant in Ottawa, Canada earlier this year.

Trudeau was the first Canadian prime minister to be invited to the US state dinner in nearly two decades, when Obama invited him and his wife to Washington in March 2016. Meanwhile, Trudeau's relationship with Donald Trump, Obama's successor, was tough.

Obama's comments come amid polls showing Trudeau's Liberal party will likely lose a majority in parliament after the general election on October 21. This is not the first time former President Obama has voiced support for a foreign leader. He posted an article supporting Emmanuel Macron before the French presidential election in 2017.

The Election Commission of Canada says Obama's article does not contravene foreign interference regulations. "It's free speech. If Obama spends money on Trudeau's campaign, that's the problem," explained the committee spokesman Pierre Cadieux.