President Donald Trump, left, watches as Corey Lewandowski, right, his former campaign manager, speaks during a campaign rally in Washington Township, Michigan. File picture: Paul Sancya/AP

Washington — A former campaign manager for Donald Trump is doubling down on his dismissive comment regarding a girl with Down syndrome.

Corey Lewandowski tweeted on Wednesday that he "mocked a liberal who attempted to politicize children" after he appeared Tuesday on Fox News Channel to discuss President Trump's hard-line immigration policy. Trump's policy has led to the practice of taking migrant children from parents charged with entering the country illegally. When another Fox panelist mentioned a story about the 10-year-old disabled girl being one of the children, Lewandowski responded with "Wah-wah."

On Wednesday, after a social media backlash about the incident, Lewandowski took to Twitter to explain himself.

Lewandowski says in his tweet that "the MSM doesn't want to talk about these policies were started under Obama." The zero-tolerance policy that has resulted in separating children began in early May under President Donald Trump.