Donald Trump's plan to vet people coming to the United States is "nonsense," retired four-star Gen. Barry McCaffrey said Monday.



The Republican presidential nominee expanded on his plans to curb immigration Monday, calling for a new ideological screening test. He cast himself as the one qualified to halt the spread of extremism, and claimed his opponent Hillary Clinton and President Barack Obama unleashed ISIS.

"The notion that we can do very good vetting on refugees coming out of Afghanistan and Syria and Libya is nonsense. If you don't have a cooperative police force and intelligence service in the country, how can you really know who you are dealing with?" McCaffrey said in an interview with CNBC's "Closing Bell."

That wasn't the only part of Trump's speech the general took issue with. He said the billionaire's contention that the U.S. should have kept the oil in Iraq "like some bandit nation" was "completely nonsensical."

McCaffrey said also disagreed with Trump's assertion that any enemy of ISIS is a friend of the U.S., noting that Iran is one of the most intense anti-ISIS countries.



—CNBC's Jacob Pramuk contributed to this report.