President Donald Trump’s special envoy to the Ukraine conflict said that recent Ukrainian attacks on Russian air bases have created a significant risk of escalation in the war.

“I’m telling you, the risk levels are going way up – I mean, what happened this weekend,” Trump’s envoy, Keith Kellogg, told Fox News. “People have to understand in the national security space: when you attack an opponent’s part of their national survival system, which is their triad, the nuclear triad, that means your risk level goes up because you don’t know what the other side is going to do. You’re not sure.”

On Sunday, the Ukrainian intelligence service, the SBU, launched a major attack on Russian airbases thousands of miles from the front lines. Kiev claims to have disabled one third of Moscow’s fleet of strategic bombers.

Washington and Moscow each possess the ability to conduct nuclear attacks via bombers, submarines, and land-based ballistic missiles, known as the nuclear triad. The White House claims that it was not informed of the attack by Kiev. However, the CIA is deeply tied to the SBU.

The SBU has conducted other provocative attacks in recent days, hitting Russian railways and bridges and reportedly killing seven civilians.

Trump said he spoke with Russian President Vladimir Putin about the attacks on Wednesday. “I just finished speaking, by telephone, with President Vladimir Putin, of Russia. The call lasted approximately one hour and 15 minutes,” Trump wrote on Truth Social. “We discussed the attack on Russia’s docked airplanes, by Ukraine, and also various other attacks that have been taking place by both sides. It was a good conversation, but not a conversation that will lead to immediate Peace. President Putin did say, and very strongly, that he will have to respond to the recent attack on the airfields.”