The White House is investigating how the details of President Donald Trump's recent tense phone conversations with Russian President Vladimir Putin concerning bilateral treaty START were leaked, The Hill reported. http://thehill.com/homenews/administration/318804-white-house-says-it-will-investigate-leaks

As it was noted the press secretary of the White House Sean Spicer expressed concern about that fact that that part of the conversation of Trump with Putin in which the U.S. President criticized the Strategic Arms Reduction Treaty became available to media.

“The idea is that the President is willing to negotiate, and the information should not be discussed away. We're doing the most important things on behalf of the whole country,” said Spicer.