It looks like the time for pulling punches is over.

Until Monday, Donald Trump and Chris Christie had gone easy on each other in the GOP presidential primary race.

On New Jersey 101.5's Ask the Governor, Christie called Trump "my friend Donald," and conceded the two would be "quite the team" on a ticket (though the governor said he's not looking to be anyone's No. 2). He's called Trump a friend on several other occasions, and talked on the campaign trail about dinners together with their wives.

When Trump infamously, brashly and unreservedly went after his other competitors in a 90-minute speech during a campaign stop in Iowa last month — comparing Ben Carson's “pathological temper” to the illness of a child molester, calling Marco Rubio “weak, like a baby,” and referring to candidate Carly Fiorina as “Carly whatever-the-hell-her-name-is.” — Christie was spared (though that didn't stop Christie from later saying Trump's comments were "not the kind of stuff that a candidate for president of the United States should be talking about.").

So far, the two have avoided turning their trademark bluster directly on one another. That is, until Monday, when Trump tweeted this:

It's an apparent response to Christie's seeming momentum in New Hampshire, where this weekend he picked up the endorsement of a leading newspaper, with others from leading political influencers soon to follow.

Christie himself may have left the door a bit too open to a not-in-New-Jersey jab when he tweeted Saturday night:

Trump, for his part, offered a typically self-referential reason for the endorsements:

Christie's faced criticism at and close to home for all the time he's spent away from New Jersey, as well. In late October, the New York Times urged him to drop out of the race and pay more attention to problems in the Garden State.

Not that the Times gave Christie a big vote of confidence for being able to solve those problems. It wrote Christie’s “role in New Jersey’s budget crisis, betrayal on affordable housing and the interlocking scandals on his watch, from Bridgegate to ‘the chairman’s flight,’ say a great deal” about his deservedness to lead.