Saber rattling amoungst the boys.

The United States switched on an $800 million missile shield in Romania on Thursday that it sees as vital to defend itself and Europe from so-called rogue states but the Kremlin says is aimed at blunting its own nuclear arsenal.

To the music of military bands at the remote Deveselu air base, senior U.S. and NATO officials declared operational the ballistic missile defense site, which is capable of shooting down rockets from countries such as Iran that Washington says could one day reach major European cities.

"As long as Iran continues to develop and deploy ballistic missiles, the United States will work with its allies to defend NATO," said U.S. Deputy Defense Secretary Robert Work, standing in front of the shield's massive gray concrete housing that was adorned with a U.S. flag.

Despite Washington's plans to continue to develop the capabilities of its system, Work said the shield would not be used against any future Russian missile threat. "There are no plans at all to do that," he told a news conference.

Before the ceremony, Frank Rose, deputy U.S. assistant secretary of state for arms control, warned that Iran's ballistic missiles can hit parts of Europe, including Romania.

When complete, the defensive umbrella will stretch from Greenland to the Azores. On Friday, the United States will break ground on a final site in Poland due to be ready by late 2018, completing the defense line first proposed almost a decade ago.

The full shield also includes ships and radars across Europe. It will be handed over to NATO in July, with command and control run from a U.S. air base in Germany.

Russia is incensed at such of show of force by its Cold War rival in formerly communist-ruled eastern Europe. Moscow says the U.S.-led alliance is trying to encircle it close to the strategically important Black Sea, home to a Russian naval fleet and where NATO is also considering increasing patrols.

http://www.reuters.com/article/us-nato-shield-idUSKCN0Y30JX