White House Council of Economic Advisers Chairman Kevin Hassett told CNBC on Monday that his departure from the post had been in the works for a while and is not linked to the recent announcement of tariffs on Mexico.

U.S. President Donald Trump said on Sunday that Hassett will "shortly" leave his position, announcing his departure in a Twitter post.

Last week, Trump threatened to impose tariffs on Mexico in retaliation for illegal immigration largely from Central America across the U.S.-Mexican border.

Commenting on the Mexico tariffs, Hassett said their near term impact will be more on Mexico than on the United States, adding he is hoping for "positive talks" between the countries.