WASHINGTON (CNN) – President Donald Trump amplified his heated immigration rhetoric on Tuesday, accusing Democrats of wanting “illegal immigrants … to pour into and infest our country,” language evoking images of pests, not human beings.

“Democrats are the problem. They don’t care about crime and want illegal immigrants, no matter how bad they may be, to pour into and infest our Country, like MS-13. They can’t win on their terrible policies, so they view them as potential voters!” he wrote.

The President’s Twitter language further escalated his dehumanizing rhetoric amid a developing humanitarian — and political — crisis on the United States’ border with Mexico, where at least 2,000 children have been separated from their parents as a result of the administration’s policy.

Last month, the administration publicly announced its decision to charge every adult caught crossing the border illegally with federal crimes, as opposed to referring those with children mainly to immigration courts, as previous administrations did.

Because the government is charging the parents in the criminal justice system, children are separated from them, with no clear procedure for their reunification aside from hotlines the parents can call to try to track their children down.

In the past weeks, heartbreaking images and audio of children crying for their parents have captured the nation’s attention as lawmakers seek to find a solution to end the separations and the White House doubles down on its insistence that it is simply enforcing the law.

Trump’s hardline immigration rhetoric was a central piece of his campaign rallying cries, beginning with his campaign announcement speech in June 2015.

“When Mexico sends its people, they’re not sending their best. … They’re sending people that have lots of problems, and they’re bringing those problems with us. They’re bringing drugs. They’re bringing crime. They’re rapists. And some, I assume, are good people,” Trump said at the time.