Russia’s “blatant violation” of a landmark arms control treaty is “untenable,” Defense Secretary James Mattis James Norman MattisBiden courts veterans amid fallout from Trump military controversies Trump says he wanted to take out Syria's Assad but Mattis opposed it Gary Cohn: 'I haven't made up my mind' on vote for president in November MORE said Thursday, adding that the Trump administration is considering diplomatic and military responses.

“Make no mistake, the current situation with Russia in blatant violation of this treaty is untenable, and we discussed the situation at length during this ministerial meeting among trusted allies,” Mattis said at a press conference following a NATO defense ministerial in Brussels.

“The United States is upholding its arms control obligations, Russia is not, and it is time now for Russia to return to compliance,” Mattis added.

ADVERTISEMENT

At issue is the 1987 Intermediate-range Nuclear Forces (INF) Treaty, which bans nuclear and conventional ground-launched ballistic and cruise missiles with ranges between 500 and 5,500 kilometers. The treaty is credited with helping end the Cold War.

The United States first accused Russia of violating the treaty in 2014. The U.S. and NATO say Russia’s 9M729 system violates the treaty.

Moscow denies it is violating the treaty. Rather, it says, the U.S. is in violation by deploying missile defenses to Europe. U.S. officials dismiss that argument, saying the systems are purely defensive and not covered under the treaty.

Mattis’s comments come after U.S. Ambassador to NATO Kay Bailey Hutchison warned the Trump administration could “take out” Russian missiles if Moscow continues to violate the treaty.

After the Russian Foreign Ministry issued a furious response to Hutchison, she tweeted that she “was not talking about preemptively striking Russia.”

Some in Congress, mostly Republicans, have argued the U.S. should abandon the treaty since Russia is not in compliance and China is free to develop the missiles since it is not a party to it.

ADVERTISEMENT

At Congress’s direction, the Trump administration announced in December it was researching a missile that would violate the treaty. The research itself is not a violation.

Mattis said the U.S. answered allies' questions about the Russian violation during discussions at the NATO ministerial and examined options to respond.

There was “no disagreement” among allies that the Russians are in violation of the treaty, he added.

Efforts to bring Russia back into compliance are ongoing, he said. If they fail, he said, there are “a host” of options to respond. He declined to elaborate, however.

“As Ambassador Hutchison has made clear, Russia must return to compliance with the INF Treaty or the U.S. will need to respond to its cavalier disregard of the treaty’s specific limits,” Mattis said. “The United States is reviewing options in our diplomacy and defense posture to do just that in concert with our allies, as always.”