The latest on Trump's immigration crackdown — and the reality of limited resources

In the three weeks since President Donald Trump took office, Americans have witnessed a frenzy of arrests and deportations.

But the president is beginning to run into the hard reality of limited resources, raising questions about whether this administration can keep up the pace. 

The speed of deportations is proving too slow for Trump. He has turned up the pressure on the Department of Homeland Security, Immigration and Customs Enforcement and his advisers to deport more people, sources told NBC News.