Donald Trump talked immigration during the first primary GOP debate Thursday night, which aired live on the Fox News Channel from Cleveland, Ohio.

He stated that he wants to build a stronger wall on the U.S.-Mexico border in order to keep people from crossing illegally.

"And I don't mind building a beautiful wall for people to come in, legally," he said. "We just need to keep illegals out."

The billionaire businessman said that immigration was not on anyone's agenda for the 2016 elections until he mentioned it during his launch. Trump made headlines when he called Mexican immigrants "rapists" and "killers," stating that the Mexican government sends over their criminals to take advantage of the U.S.

"They send over their criminals because they don't want to deal with them and pay for them," he said regarding the amount of tax dollars it costs to hold prisoners.

When asked twice about what evidence he has that the Mexican government is sending over criminals, Trump said that Border Patrol agents confirmed to him that it is true.

Trump recently told Fox News' Bill O'Reilly that he is sure that he could make Mexico pay for the wall he wants to build if he becomes president.

"Bill, they are making a fortune, Mexico is making a fortune off the United States, it's becoming the new China in terms of trade -- they're killing us at the border," Trump said after O'Reilly asked him the question twice.

The business mogul says he should become the next U.S. president because he has what it takes to strengthen the economy.

"This country right now owes $19 trillion in debt and they need somebody like me to straighten out that mess," he said.  

"We don't win anymore. We don't beat China and Japan in trade. We can't beat Mexico at the border or in trade," he added.

Trump was a main focus of Thursday night's debate.