The Obama administration has accused Russia of violating a 1987 nuclear missile treaty by testing a ground-launched cruise missile and says the U.S. is prepared for immediate high-level dialogue with Moscow over the matter.
An administration official told Fox News in a statement that the violation "is a very serious matter which we have attempted to address with Russia for some time now." The New York Times first reported the accusation.
President Obama informed Russian President Vladimir Putin in a letter Monday of the U.S.' determination that Russia broke the agreement. The official said the U.S. is prepared to engage in "senior-level bilateral dialogue immediately" with Russia with the goal of assuring Washington that Moscow will return to compliance with the treaty.
"The United States is committed to the viability of the I.N.F. Treaty," the official said. "We encourage Russia to return to compliance with its obligations under the Treaty and to eliminate any prohibited items in a verifiable manner."
According to the Times, Russia started testing the missiles as early as 2008, and the Obama administration flagged them as a possible violation at the end of 2011.
Russian officials have said they looked into the allegations and consider the matter closed.
Obama's most senior advisors recently unanimously agreed that the tests was a serious violation of the treaty, the Times reported. The State Department will publicly reveal the accusation in an annual report on compliance with arms control agreements Tuesday.
The treaty confrontation comes at a highly strained time between President Obama and Russian President Vladimir Putin over Russia's intervention in Ukraine.
In raising the issue now, the U.S. appears to be placing increased pressure on Russia and trying to further isolate it from the international community. The European Union and the United States plan to announce new sanctions against Russia this week in the face of U.S. evidence that Russia has continued to assist separatist forces in Ukraine.
The public finding comes in the wake of congressional pressure on the White House to confront Russia over the allegations of cheating on the treaty. The treaty, which President Ronald Reagan signed with Soviet leader Mikhail Gorbachev, banned all U.S. and Russian land-based ballistic and cruise missiles with ranges between 300 miles and 3,400 miles.
Obama, who has made nuclear disarmament a key foreign policy aim, has little interest in having Russia pull out of the treaty altogether. Obama won Senate ratification of a New START treaty, which took effect in February 2011 and requires the U.S. and Russia to reduce the number of their strategic nuclear weapons to no more than 1,550 by February 2018.
Obama last year announced that he wants to cut the number of U.S. nuclear arms by another third and that he would "seek negotiated cuts" with Russia, a goal now complicated by the accusation of a missile treaty violation.
The Obama administration has informed Congress and U.S. allies of its decision to seek Russian compliance.
The Associated Press contributed to this report