The two senior Trump administration officials Mnuchin and Lighthizer are frequently divided on economic policy issues but shared the same opinion that the tariffs were a bad idea, CNBC reported, citing a source close to the White House.
Trump made the decision to announce the tariffs after getting "riled up" by a conservative radio program on the surge in illegal immigration, the report said.
Although Mnuchin and Lighthizer opposed Trump's idea, White House senior policy adviser Stephen Miller played a key role in promoting it, the report said, while noting that the aide has long championed fiercely hawkish views on immigration.
READ MORE: Trump Tariffs on Mexico to Have ‘Severe' Consequences for Texas — US Lawmaker
An increasing number of migrants from Central America have been arriving to the US border with Mexico in recent months. Trump has called the surge of arrivals a crisis and declared a national emergency in February to secure funds to build a border wall.