"It's unfortunate that a private citizen can meet with the defense minister and have a communication and the United States can't," said White House National Security Council spokesperson John Kirby.
"That is something that we want to solve. This is why we continue to try to get the military lines of communication back open because when they're not open and you have a time like this when tensions are high, miscalculations also, then the risk goes high."
Kirby said that administration officials "look forward to hearing from Secretary Kissinger when he returns, to hear what he heard, what he learned, what he saw."