Editor’s Note: New Jersey Gov. Chris Christie will respond to Donald Trump in an interview first airing on “The Lead with Jake Tapper” at 4 p.m. ET.

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Donald Trump hit Chris Christie on Monday morning just a few days after the New Hampshire Union Leader endorsed the New Jersey governor

The Union Leader knocked Trump in its endorsement of Christie

Washington CNN  — 

Donald Trump took a swipe at Chris Christie on Monday morning, just a few days after the New Hampshire Union Leader made a high-profile endorsement of the New Jersey governor.

“How is Chris Christie running the state of NJ, which is deeply troubled, when he is spending all of his time in NH? New Jerseyans not happy!” Trump tweeted.

The Union Leader endorsed Christie on Saturday, giving a boost to Christie while also taking a shot at Trump.

“Other candidates have gained public and media attention by speaking bluntly. But it’s important when you are telling it like it is to actually know what you are talking about,” Union Leader publisher Joseph McQuaid wrote in the endorsement.

Trump has scrapped with many other Republican opponents – including repeated hits on Jeb Bush, Carly Fiorina and Marco Rubio – but has largely left Christie untouched.

The billionaire businessman has a habit this election cycle of knocking particular primary opponents after they appear to have risen in the polls or faced increased media scrutiny.

The New Jersey governor is hoping that the election cycle’s increased focus on national security – in the wake of the Paris terror attacks – will encourage GOP primary voters to give him a second look, particularly in the Granite State.

Christie, who’s spent more time in New Hampshire than any other Republican 2016er, is back in the state Monday where he’s holding a town hall and is scheduled to receive an endorsement of real estate developer Renee Plummer, a key political figure in the state.

Requests for comment from the Christie and Trump campaigns were not immediately returned Monday.