Hours after being sworn in as president for a second time, President Trump signed executive orders declaring a national emergency on the U.S.-Mexico border and calling for more barriers as part of an aggressive crackdown on undocumented immigrants.

Those policy changes were expected to start rolling in fast in the first hours and days of his second term after a campaign in which Trump vowed to launch the largest deportation operation in the country’s history.

Trump is declaring a national border emergency and taking others steps to curb immigration. Here's what that means.