White House: Leaking Trump briefing materials a 'fireable offense'

The White House on Wednesday said that leaking President TrumpDonald John TrumpMinneapolis erupts for third night, as protests spread, Trump vows retaliation Stocks open mixed ahead of Trump briefing on China The island that can save America MORE’s briefing materials could be a “fireable offense,” responding to reports that the president disregarded a warning against congratulating Russian President Vladimir Putin on his reelection. 
“If this story is accurate, that means someone leaked the President’s briefing papers. Leaking such information is a fireable offense and likely illegal,” a senior White House official said in a statement. 
The Washington Post reported late Tuesday that a section of Trump’s briefing materials for his call with Putin read “DO NOT CONGRATULATE” in all-capital letters. 
Trump also did not follow instructions to condemn Putin over the poisoning of a former Russian double agent and his daughter in the U.K., according to the Post.
The White House has not confirmed the report, but multiple news outlets followed with similar stories. The person or people responsible for the leak have not been publicly identified.
It’s not clear whether Trump received the warning before getting on the call with Putin. The Post reported that national security adviser H.R. McMaster briefed the president in person about the call, but did not mention the issue.
The leak sparked yet another Russia-related controversy for the embattled White House, which is under the microscope in special counsel Robert MuellerRobert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's probe into Moscow's interference in the 2016 presidential election. 
It renewed questions about Trump’s approach toward Russia, which is frequently at odds with U.S. allies, Congress and some members of his own administration. 
Instead of confronting Putin about a host of tense issues, Trump not only congratulated the Russian leader but also discussed a possible summit meeting with him.
“An American president does not lead the Free World by congratulating dictators on winning sham elections,” Sen. John McCainJohn Sidney McCainHow Obama just endorsed Trump Former Texas Rep. Sam Johnson dies at 89 Trump's needless nastiness and cruelty will catch up with him MORE (R-Ariz.) said in a statement following the call.
The fact that sensitive briefing materials leaked out also alarmed top administration officials, who are concerned members of Trump’s own staff could be trying to undermine him. 
“Illegal or not if you’re leaking Presidential talking points you’re not serving the President and should not be @WhiteHouse,” tweeted Sam Winograd, a former National Security Council official in the Obama White House.