Donald Trump Donald John TrumpBiden leads Trump by 36 points nationally among Latinos: poll Trump dismisses climate change role in fires, says Newsom needs to manage forest better Jimmy Kimmel hits Trump for rallies while hosting Emmy Awards MORE on Thursday fired back at criticism from presidential rival Rick Perry.

The former Texas governor "failed on the border. He should be forced to take an IQ test before being allowed to enter the GOP debate," Trump tweeted Thursday afternoon.

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The comment came hours after Perry issued a blistering statement that said Trump was mistaken on border security and only offered "a toxic mix of demagoguery and nonsense."

It was another in a series of jabs between the two candidates, to which Trump countered in another tweet by saying that Perry "doesn't understand what the word demagoguery means."

Perry, whose "oops" moment during a televised debate during the 2012 campaign kneecapped his previous White House bid, has himself addressed the relationship of intelligence and the presidency.

"Running for president is not an IQ test," Perry said in December when preparing to exit office.

"It is a test of an individual’s resolve; it is a test of an individual’s philosophy; it is a test of an individual’s life experiences," Perry said then, alluding to his 14-year tenure as governor.

Both Trump and Perry are running for the White House in a packed field of 2016 Republican candidates, and illegal immigration is a major topic in both of their campaigns.

Trump has skyrocketed in polls in recent weeks, helping to solidify his position among the top 10 GOP candidates who will be allowed to participate in the first debate next month. Perry has worked to make it on that stage.

Participants in that debate will be based on national polling averages. Trump is currently ranked second in the RealClearPolitics average of polls, while Perry is 10th.