U.S. President-elect Donald Trump's vow to impose tariffs on China and Mexico unless they stem the flow of fentanyl and migrants across the U.S. border could impel deeper cooperation from those governments on drug policing,

Neither his claim that border crossings are an unchecked “invasion” nor his depiction of drugs pouring across an unguarded border has any basis in federal data.

Beijing’s foreign ministry says fentanyl is US’ own problem and that China provided support ‘out of a humanitarian spirit’.

"Thousands of people are pouring through Mexico and Canada, bringing Crime and Drugs at levels never seen before," Trump said.