Asked to name the biggest threat to Canada’s security during an election debate, Mark Carney, the country’s prime minister and Liberal Party leader running to win a full term, gave a surprising answer: “China.”

Analysts saw it as an attempt to distance himself from the country amid heightened scrutiny on his own past work there.

Mr. Carney, a former central banker and business executive, dealt with the Chinese establishment in his recent private-sector roles for companies with investments in China.

But what was once an asset — experience working with a rising global power — has become a political liability in Monday’s national elections.

Mr. Carney and the Liberals have come under criticism for supporting a parliamentary candidate with connections to groups representing China’s Communist Party in Canada. Foreign interference in diaspora communities in Canada by China, India and other nations has been a concern for both parties, and the subject of inquiries.

The relationship between Canada and China sharply deteriorated following a diplomatic crisis that began when Canada detained a Chinese executive in 2018 on behalf of the United States.