US national security spokesperson John Kirby told the BBC that the US government was scrambling to get to the bottom of the leaks.
"This was a series of dangerous leaks. We don't know who's responsible, we don't know why. And we are assessing the national security implications, and right now there is also a criminal investigation," he said on Wednesday.
"We want to get to the bottom of this, we want to find out who did this and why."