(CNN) NATO diplomats are dumbfounded by President Donald Trump’s barrage of acidic rhetoric at the annual summit in Brussels on Wednesday.

Trump came out brawling in his first public comments, accusing NATO ally Germany of being “a captive of Russia,” calling members of the alliance “delinquent” in their defense spending and insisting they increase it “immediately.”

“It’s like the world has gone crazy this morning,” one senior European diplomat told CNN. “Trump’s performance was beyond belief.”