US President-elect Donald Trump vowed that he would impose a 25% tariff on all products coming into the United States from Mexico and Canada on his first day in office .

“As everyone is aware, thousands of people are pouring through Mexico and Canada, bringing Crime and Drugs at levels never seen before,” Trump wrote in a post on his social media platform Truth Social.

Trump said that on January 20, in one of his first executive orders, he would sign all the necessary paperwork to levy a 25% tariff on all products arriving from the U.S.’s North American neighbours.

“This Tariff will remain in effect until Drugs, in particular, Fentanyl, and all Illegal Aliens stop this Invasion of our Country!” he wrote. “Both Mexico and Canada have the absolute right and power to easily solve this long-simmering problem. We hereby demand that they use this power, and until such time that they do, it is time for them to pay a very big price!”

Trump said in another Truth Social post that he also would levy an additional 10% tariff on top of existing tariffs on Chinese products coming into the United States.

“I have had many talks with China about the massive amounts of drugs, in particular Fentanyl, being sent into the United States – But to no avail,” he wrote. “Representatives of China told me that they would institute their maximum penalty, that of death, for any drug dealers caught doing this but, unfortunately, they never followed through.”

Trump said the additional tariff on Chinese goods would remain in place until it stops allowing illegal drugs to pour into the U.S.

Throughout his presidential campaign, Trump vowed to declare a national emergency and use military assets to deport a record number of immigrants who are in the United States illegally.

Some Economists warn that slapping tariffs on products shipped into the United States could drive up inflation and interest rates and result in higher consumer prices.