Echoing right-wing media and commentators, President Donald Trump on Monday warned that a caravan of Central Americans headed for the U.S.-Mexico border amounts to an “invasion” of America.

Trump made the claim in a morning tweet that reflected a major part of his midterms closing argument: Democrats are for increasing immigration, which he says will bring crime and transfer federal benefits away from American citizens. It is designed to fire up his conservative base in a turnout election cycle.

“Many Gang Members and some very bad people are mixed into the Caravan heading to our Southern Border,” he wrote without supporting evidence.

“Please go back, you will not be admitted into the United States unless you go through the legal process,” the president warned in a message directly to the migrants.

Many Gang Members and some very bad people are mixed into the Caravan heading to our Southern Border. Please go back, you will not be admitted into the United States unless you go through the legal process. This is an invasion of our Country and our Military is waiting for you!

— Donald J. Trump (@realDonaldTrump) October 29, 2018

He then turned to talking points that are frequently used on right-wing media networks like Fox News, which he watches frequently.

“This is an invasion of our Country,” the commander in chief said, adding: “and our Military is waiting for you!”

Last week, he ordered thousands of troops to the border after declaring the caravan a national emergency. Immigration experts and Democratic lawmakers have criticized the move.

But the president has shown no signs of easing his rhetoric about the migrants, and is likely to continue the warnings during a string of campaign rallies before next Tuesday’s crucial elections, in which his presidency is a major topic and which will decide the fate of his agenda.