(CNN) At a lunch at the White House on Monday with more than a dozen UN ambassadors, President Trump poked some fun at his own UN Ambassador Nikki Haley.

In front of the UN Security Council, President Donald Trump jokingly says... Ambassador Nikki Haley "can easily be replaced." pic.twitter.com/Gwi8CifDZ6 — Nigel Robertson (@thetopstoryWYFF) April 24, 2017

"Does everybody like Nikki?" Trump asked the assembled ambassadors as Haley sat by his side. Amid laughter Trump added: "Otherwise, she can easily be replaced."

Cue awkward laughter.

Now, Trump was joking. And everyone in the room -- including Haley -- understood that. But, that doesn't mean he was entirely kidding.

Two things we know about Trump suggest that beneath his attempt at humor was a hard-edged point.

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