Corey Lewandowski, President Donald Trump's former campaign manager, on Tuesday night appeared to mock an anecdote about a 10-year-old girl with Down syndrome who was reportedly separated from her family at the US-Mexico border.

The exchange happened during a discussion on Fox News about the Trump administration's "zero tolerance" border policy.

In recent days, the administration has faced growing bipartisan criticism over the policy, in which all adult migrants are being referred for criminal prosecution when they cross the US border illegally, which leads children to be separated from the adults they're traveling with.

The Trump administration's enforcement of its new "zero tolerance" immigration policy sparked a shouting match during a Fox News segment on Tuesday.

"Look, I read today about a 10-year-old girl with Down syndrome who was taken from her mother and put in a cage," Zac Petkanas, a former Hillary Clinton campaign aide, said.

"Womp womp," Corey Lewandowski, President Donald Trump's former campaign manager, said mockingly.

"Did you just say 'womp womp' to a 10-year-old girl with Down syndrome being taken from her mother?" Petkanas said.

The conversation quickly went off the rails as the two tumbled into a shouting match.

"What I said is that you can pick anything you want, but the bottom line is very clear," Lewandowski said. "When you cross the border illegally, you have given up the right--"

"How dare you, how absolutely dare you, sir?" Petkanas said.

Petkanas seemed to be referring to a Wall Street Journal report that mentioned a girl who was separated from her mother and her brother as they attempted to cross the US-Mexico border. The girl and her mother were sent to different detention facilities, according to the report.

The Trump administration has recently faced growing bipartisan criticism over its new policy that automatically refers adult migrants who have entered the US illegally for criminal prosecution. The move invariably leads to children being separated from the adults they're traveling with.

Watch the clip here: