U.S. says Russia violated 1987 nuclear missile treaty

In an escalation of tensions, the Obama administration accused Russia on Monday of conducting tests in violation of a 1987 nuclear missile treaty, calling the breach "a very serious matter" and going public with allegations that have simmered for some time.

The treaty confrontation comes at a highly strained time between President Barack Obama and Russian President Vladimir Putin over Russia's intervention in Ukraine and Russia's grant of asylum to National Security Agency leaker Edward Snowden.

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An administration official said Obama notified Putin of the U.S. determination in a letter Monday. The finding will be included in a State Department annual report on compliance with arms control treaties that will be released Tuesday.

The U.S. says Russia tested a new ground-launched cruise missile, breaking the Intermediate-Range Nuclear Forces Treaty that U.S. President Ronald Reagan signed with Soviet leader Mikhail Gorbachev.

1st public accusation

The official, who spoke on the condition of anonymity because he was not authorized to discuss sensitive information publicly by name, said the U.S. is prepared to hold high-level discussions on the issue immediately "with the aim of assuring the United States that Russia will come back into compliance with its treaty obligations."

Though the U.S. has raised the issue with Russia in the past through diplomatic channels, it had not previously made the accusation publicly. Russian officials say they have looked into the allegations and consider the matter closed. The New York Times first reported the U.S. conclusion Monday evening

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 banned all U.S. and Russian land-based ballistic and cruise missiles with ranges between 480 kilometres and 5,470 kilometres.