Donald Trump's Homeland Security Secretary Markwayne Mullin clashed so heatedly with a Democratic lawmaker at a committee hearing that even the Republican chairman lost patience with him.

Mullin got into a finger-pointing argument with blue-haired Democratic Representative Rosa DeLauro on Capitol Hill Thursday during a debate over the administration's child separation policy for undocumented migrants.

Mullin accused DeLauro of being a 'hypocrite' for being outraged over children separated under Trump when she 'didn't say a word' about the minors who went missing during Joe Biden's tenure.

'Don't interrupt me!' DeLauro screamed at Mullin, pointing her finger at the DHS secretary.

'Don't you point your finger at me. Don't be a hypocrite,' he replied. 'Don't you be a hypocrite then. You should be as upset about the 450,000 kids that were lost. You didn't say a word about it! For four years you never said a word!'

Republican Committee Chair Mark Amodei stepped in to tell Mullin to let the Democratic member continue with her questions, after he kept interrupting the lawmaker to trade jabs.

'Mr. Secretary, if you would like four minutes for a closing statement when everybody's done, I'll give you that. But while members are on their eight minutes, I need them to have their eight minutes,' Amodei said.

Mullin refused to comply with Amodei's request, leading the Republican chair to step in again: 'Mr. Secretary, the floor is hers. Actually, I gave it to her. You know, there is a chairman of a committee. That's me. I gave it back to her.'

The Homeland Secretary continued clashing with DeLauro, forcing Amodei to step in again and order Mullin to stop interrupting. 

'We are going to have something resembling order here,' Amodei said. 'The time is the ranking member’s. If you would like to respond later on there are methods to do that but it’s not a who can talk louder into the mic.'

'I will not let her sit there and lie and accuse me of something that’s ridiculous,” Mullin barked back. 

'You know, this is the legislative branch and it’s my hearing and so I’m going to try to some extent to control it moderately,' Amodei added. 

Earlier in the argument, Amodei threatened to postpone the hearing unless both sides agreed to not interrupt each other. 

'This is not Meet the Press or Fox News or whatever for anybody involved, it’s what’s the question, what’s the answer,' he said. 

Mullin is Trump's second DHS secretary, having replaced Kristi Noem in March after a string of personal and professional scandals marred her tenure and prompted Democrats to cut off funding to the department for months.

Mullin, like Noem, has repeatedly claimed that 450,000 minors went missing during Biden's tenure after crossing the southern border on their own. 

Homeland Security claimed earlier this month that it had located 146,000 of those minors.