US defense officials, speaking on condition of anonymity, told several sources on Tuesday that Russia had notified Washington of the missile test "before the crisis started in Ukraine." Under the terms of a 2010 agreement on nuclear weapons, the US and Russia have agreed to notify each other in advance of any such test-launches.

"This was a previously notified and routine test launch of an ICBM," said Caitlin Hayden, a spokeswoman for the White House's National Security Council. "Such advance notifications are intended to provide transparency, confidence, and predictability and to help both sides avoid misunderstandings."

Defense Ministry spokesman Igor Yegorov told the state-run RIA news agency that an RS-12M Topol missile was launched from Astrakhan and hit its target in Kazakhstan successfully. The road-mobile missile has a reported maximum range of 10,000 kilometers (6,200 miles). The Kapustin Yar launch site near the Volga River is roughly 450 kilometers to the east of the border with Ukraine, but the missile flew east, away from Ukraine. Russia's last reported test of such a projectile was on December 28.

The diplomatic atmosphere between Washington and Moscow remains unusually tense amid the deployment of Russian troops in the Crimean Peninsula of southern Ukraine. Russia has said it was acting on a request to protect the region's majority ethnic-Russian population, a threat the US has described as "imaginary."

The world's two largest nuclear powers signed the latest iteration of the bilateral Strategic Arms Reduction Treaty (also known as "New START") in 2010, pledging to reduce the size of their arsenals. A further reduction is believed to be a possibility in the near future, although both sides are also modernizing their nuclear capabilities.

msh/av (AFP, Reuters)