President Donald Trump has taken increased control of negotiations over North Korea’s nuclear weapons program, sidelining his own top negotiator and dismissing the warnings of top intelligence and foreign policy advisors in the wake of last month’s failed summit in Vietnam, officials familiar with the developments tell TIME.

In recent days, Trump shut down an effort by Stephen Biegun, nominally the Administration’s lead negotiator with Pyongyang, to reestablish a back channel through the North’s United Nations mission in New York, according to four U.S. and South Korean officials.

At the same time, Trump continues to dismiss the conclusions of the CIA, State and Defense Departments and other agencies that North Korea will not abandon its nuclear weapons program, continuing to insist that he and Kim can negotiate a deal, according to two U.S.officials.