US Senator tries to start a fight with a witness in the middle of a hearing

A US Senator has been yelled at to sit down after trying to start a fight with a witness during a hearing.

The Senate Health, Education, Labor and Pensions Committee hearing was meant to be focusing on how unions can help working families, according to PBS.

However, a war of words erupted between Oklahoma Senator Markwayne Mullin read out some tweets from Sean O’Brien, the president of the International Brotherhood of Teamsters.

Senator Mullin took issue with O'Brien saying the Republican wasn't a 'self-made man' and insisted that he worked hard to set up his plumbing company before becoming a politician.

Some of the other tweets allegedly called Mullin a 'greedy CEO', a 'clown' and a 'fraud'.

"I appreciate your demeanor today," Senator Mullin said to O'Brien during the hearing.

"It's quite different.

"But after you left here, you got pretty excited about the keyboard.

"In fact, you tweeted at me, one, two, three, four, five times."

He then read out another tweet where O'Brien apparently said 'you know where to find me...any time, any place, cowboy'.

So, Senator Mullin decided this was the perfect moment to throw hands.

"Sir, this is a time. This is a place," Mullin said.

"If you want to run your mouth, we can be two consenting adults. We can finish it here."

O'Brien responded with: "OK, that's fine. Perfect."

Mullin asked if he wanted to 'do it now' and the Teamsters President said: "I'd love to do it right now."

Mullin replied: "Well, stand your butt up, then. You stand your butt up."

He then launched off his chair like he was about to fight and Senator Bernie Sanders told his fellow politician to sit down.

“Stop it. You're a United States senator. This is a hearing, and God knows the American people have enough contempt for Congress, let’s not make it worse," the Vermont Senator yelled.

PBS says the two traded words for several minutes as Sanders tried to get them to settle down.

Senator Sanders called the whole thing 'absurd'.

“We were there to be talking about, and did talk about, the crisis facing working families in this country, the growing gap between the very rich and everybody else and the role that unions are playing in improving the standard of living of the American people,” Sanders said.

“We’re not there to talk about cage-fighting.”