The Pentagon is planning to fortify its defenses in Europe by investing in and deploying upgraded weapons to oppose Russia’s alleged violation of a crucial arms control pact, a senior U.S. defense official said Tuesday, according to reports. Brian McKeon, U.S. principal deputy undersecretary of defense for policy, called Russia's move an “indirect threat” to the U.S.

America accused Russia in July 2014 of breaching the 1987 Intermediate-Range Nuclear Forces (INF) treaty, which prohibits land-based intermediate-range missiles. According to the U.S., Moscow violated the accord by developing and testing a banned ground-launched cruise missile. However, Russia has denied the accusation.

"The evidence is conclusive," McKeon told members of a subcommittee of the House Armed Services Committee, according to the Associated Press (AP). "Russia has tested this ground-based system well into the ranges covered by the INF treaty. We are talking about a real system and not a potential capability." McKeon added that the U.S. was boosting its air defense systems in retaliation for Russia’s violations.

"We are investing in the technologies that are most relevant to Russia's provocations, developing new unmanned systems, a new long-range bomber, a new long-range stand-off cruise missile and a number of innovative technologies," McKeon said, according to the AP.

McKeon said that the U.S. forces maintained a constant air, land and sea presence in the Baltics and central Europe to conduct joint military exercises, reassure its allies and improve their capacities. America is advancing its nuclear arsenal, working with NATO to boost promptness and urging allies to invest more in defense, McKeon reportedly said.

However, the response seemed unsatisfactory to some Republicans. Mike D. Rogers, Alabama’s Republican Representative and the chairman of the House Armed Services Strategic Forces subcommittee, said that the Obama administration failed to announce specific actions in response to the alleged Russian breach of the INF treaty.

“This is a longstanding violation,” Rogers said, according to the New York Times. “It should not be blended in.”

Sharing the same opinion, Ted Poe, a Texas Republican, said that there was no development in pulling the Russians into a serious discussion about the breach, the Times reported.