Trump's comments came in the second part of an interview conducted on Tuesday with Fox News anchor Sean Hannity. They signaled a further softening in his immigration position as he girds for a battle against Democrat Hillary Clinton in the Nov. 8 election and faces pressure to bolster support among moderate voters and minority groups.

Trump, who defeated 16 rivals for the Republican presidential nomination in part based on his opposition to illegal immigrants, said he would not permit American citizenship for the undocumented population and would expel lawbreakers.

To qualify to remain in the United States, Trump said, illegal immigrants would have to pay back taxes.

"No citizenship. Let me go a step further - they'll pay back taxes, they have to pay taxes, there's no amnesty, as such, there's no amnesty, but we work with them," Trump said.