President-elect Donald Trump’s pick for Border Czar, Tom Homan, issued a stark warning on Tuesday to any Democratic officials obstructing deportations, reminding them that they could be jailed for obstructing Immigration and Customs Enforcement (ICE).

“I’ve said a hundred times, and last week, don’t cross that line. It is a felony to knowingly harbor and conceal an illegal alien from immigration authorities, don’t test us. The nation wants a safe country,” said Homan, speaking at Eagle Pass, Texas.

Homan’s warning came after multiple Democrat mayors and governors, including Massachusetts Gov. Maura Healey (D), promised to resist President Trump’s plan to remove people from the country who have no legal right to be here.

Gov. Healey promised that she would not allow the Massachusetts State Police to assist in deportation measures if they were ordered to do so by the Trump Administration.

Denver Mayor Mike Johnston, a staunch supporter of his city’s “sanctuary city” policy, emerged as one of the most vocal opponents of deportation plans.

The city already actively avoids turning petty criminals in the country illegally over to ICE for deportation, but Mayor Johnston suggested that he would take this resistance even further.

He suggested that the only way Trump could carry out his mass deportation plan in Denver is if he used the National Guard of Alabama and Texas to invade Colorado.

He even threatened to station the Denver Police Department along the county border to block any authorities from entering to deport illegal aliens, apparently endorsing an armed rebellion by Denver’s law enforcement against the federal government.

“More than us having DPD stationed at the county line to keep them out, you would have 50,000 Denverites there,” said Johnston. “It’s like the Tiananmen Square moment with the rose and the gun, right? You’d have every one of those Highland moms who came out for the migrants. And you do not want to mess with them.”

Homan had a harsh response for Johnston and his threats.

“Me and the Denver mayor, we agree on one thing: He’s willing to go to jail; I’m willing to put him in jail,” said Homan, “It’s a felony if you knowingly harbor and conceal an illegal alien from immigration authorities, It is also a felony to impede a federal law enforcement officer.

“If he don’t wanna help, that’s fine. He can get the hell out of the way,” said Homan.