President Obama on Thursday dismissed Republican warnings about the dangers of illegal immigration as nothing more than "tales" meant to frighten voters.

"Think about how much better off our country would be if Republican politicians didn't try to scare voters with tales of immigrants flooding our borders," Obama said in a speech before the Congressional Hispanic Caucus Institute.

Obama encouraged the audience to show their support for immigration reform at the ballot box. When he mentioned the immigration position staked out by many Republican presidential candidates, the audience booed, but Obama said booing isn't enough.

"They can't hear the boos; but they can hear your votes," he said.

"That's not leadership," Obama said. "Fanning the flames of intolerance then acting all surprised when fire breaks out" is not how one leads the nation, Obama said, indirectly referring to comments made by candidates such as Donald Trump about illegal immigrants.

"When Mexico sends its people, they're not sending their best," Trump said when he announced his candidacy. "They're sending people that have lots of problems. They're bringing drugs. They're bringing crime. They're rapists."

Obama said the Republicans looking to succeed him want to turn back the clock, particularly where the nation's immigration laws are concerned.

When it comes to his executive action on limiting some deportations, Obama promised the crowd filled with Latino luminaries that he was not giving up.

"Although it is taking us longer than we hoped we are on the right side of the law, and I will keep fighting to prove it," he vowed.