Air Force Gen. John Hyten, commander of U.S. Strategic Command, said April 4 he is “reviewing” the Intermediate-Range Nucle        ar Forces Treaty, underscoring the Defense Department’s focus on addressing Russia’s violation of the 1987 accord.

U.S. officials in February said Russia has deployed a ground-launched nuclear-capable cruise missile and that the Trump administration plans potential responses to the INF breach. Sen. John McCain (R-Ariz.) said April 4 during a Senate Armed Services Committee hearing that the development “calls into question basic assumptions about U.S. nuclear policy – assumptions we must be prepared to re-evaluate given the new realities of our strategic environment.”

Hyten said the breach “is a concern to us because we have not seen that for quite some time.” The Pentagon’s upcoming Nuclear Posture Review, which is expected to be completed in six months, will consider military response options to Russia’s violation. The administration’s priorities for this review, Hyten said, will be based on an assessment of the threat scenarios from Russia, China, North Korea, and Iran.

“A single ground-launched cruise missile is not a significant threat to the United States or our allies. It shows the beginning of a deployment of a structure that could be a threat in the future,” Hyten said. However, if deployed in a significant number, such a cruise missile would threaten most of Europe, he said: “We have no defense for it, especially in defense of our European allies.”

“I am reviewing the INF agreement,” Hyten said, indicating that the U.S. might take a different approach toward the treaty. He noted, however, that he has not been directed to review or consider changing the U.S. approach toward the U.S.-Russian New START treaty.

He spoke in support of the nuclear arsenal limits set by New START and said the agreement gives each country a helpful understanding of the other’s capabilities. “We get huge value from a bilateral, verifiable treaty that allows us to see exactly what our adversaries are doing from a strategic weapons perspective,” Hyten said.

Hyten during the hearing also warned of Defense Department budget and schedule constraints.

“Any recapitalization program delays will further diminish these capabilities and affect our ability to execute our mission,” he said of the program to update each leg of the nuclear triad. The general said another continuing resolution past the April 28 expiration of the current short-term spending program would make it difficult to start new programs and would ultimately become a “very significant issue in terms of cost to the taxpayers as well as risks to national security.”

Hyten also said that while the U.S. should maintain its focus on nuclear weapons life-extension programs to ensure the arsenal remains reliable, “fundamentally at some point in the future we have to be able to transition to those new weapons.”