This article is more than 6 years old

This article is more than 6 years old

The Obama administration in Washington has accused Russia of conducting missile tests in violation of a 1987 nuclear treaty, calling the breach "a very serious matter" and bringing into the public sphere allegations that have simmered for some time.

The treaty confrontation comes at a highly strained time between the US president and his Russian counterpart, Vladimir Putin, over Russia's intervention in Ukraine and granting of asylum to Edward Snowden, who exposed widespread surveillance and collection of innocent people's data by US intelligence agencies.

An administration official said Obama had notified Putin of the US objections in a letter Monday. The finding is to be included in a US state department annual report on compliance with arms control treaties due for release on Tuesday.

The US is accusing Russia tested a new ground-launched cruise missile, breaking the Intermediate-Range Nuclear Forces Treaty that Ronald Reagan signed with Mikhail Gorbachev during the Soviet era.

"This is a very serious matter which we have attempted to address with Russia for some time now," an administration official said in a statement.

"We encourage Russia to return to compliance with its obligations under the treaty and to eliminate any prohibited items in a verifiable manner."

Another official said the US was prepared to hold high-level discussions on the issue immediately.

The US has raised the matter with Russia in the past through diplomatic channels but has 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 US conclusion on Monday evening.

In raising the issue now the US 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 US 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 US and Russian land-based ballistic and cruise missiles with ranges between 300 miles (480km) and 3,400 miles (5,470km).

Reuters and the Associated Press contributed to this report