It was leaked to the Washington Post on Tuesday night that, when Donald Trump congratulated Vladimir Putin for his re-election as president of Russia, he was holding briefing materials that had the words “DO NOT CONGRATULATE” written in all-caps on it. Ha ha ha. Then it was immediately leaked to reporters that Trump was very angry about the leak.
Trump was, apparently, asking tons of friends and advisers on Tuesday night who they thought had leaked the leak, a fact that was subsequently leaked to CNN. It was also leaked that chief of staff John Kelly is furious about the leak and will be addressing the matter of leaks with aides on Wednesday—a meeting whose contents will, presumably, be leaked.
One reason why Trump was especially up in arms about this leak is that it could have only come from a small group of people with access to this sensitive information, as a leaker noted to Axios. So DO NOT CONGRATULATE Trump, as he is very far from winning his war on leaks.