U.S. President Donald Trump's top homeland security official joined officers as they carried out an immigration arrest in New York City on Tuesday, the latest effort to promote Trump's nationwide crackdown as enforcement has intensified in recent days.

President Donald Trump’s immigration crackdown and effort to deport massive numbers of people hit the nation’s largest city early Tuesday, as immigration officers and federal agents fanned out across a city where 1 in 3 residents were born in another country.

The administration has mobilized military units to head to the southern border and increased immigration raids in major cities. Here's what to know.