Rome, June 4 (LaPresse) – Keith Kellogg, special envoy of U.S. President Donald Trump for Ukraine, stated in an interview with Fox News that Kiev carried out a "very bold attack" against Russian military airports, but warned that such a move significantly increases the risk of escalation. "Risk levels are rising sharply," he said, "in the realm of national security, when you attack an adversary’s survival system, namely their nuclear triad, the risk level rises because you don’t know what the other side will do, you’re not sure." According to Kellogg, it is "very clear" that risk levels increase "and I think that is exactly what we are trying to avoid."