The first sailors are now on station at the controversial missile defense shield in Romania, Navy Region Europe announced Monday.

The sailors arrived last month as part of an initial wave that will "lay the groundwork for a full team deployment."

The announcement means the AEGIS Ashore missile defense facility in Deveselu is a step closer to becoming operational. Russian President Vladimir Putin has repeatedly condemned the facility, claiming the shield is aimed at upsetting the strategic balance of power in Europe.

Lt. Cmdr. Joshua Lewis, the executive officer for the AEGIS Ashore Missile Defense System, said the advance team is using the time to setting up procedures and organizing workflow for the new facility.

"There's real value in actually seeing the facility first hand and formulating how you want to do business based on first-hand experience," Lewis said. "We can also liaison with the base team to formulate procedures and memorandums and understanding between us."

The Deveselu site is the first of two missile defense shields planned for Eastern Europe. The second site is scheduled to open in Poland in 2018. The U.S. has said the missile shields are intended to thwart an intermediate range missile attack on Europe from a rogue state such as Iran.

But Russia sees the shields as a direct threat to its position in the world.

Putin told Russian lawmakers in December that he views the missile shields as destabilizing.

"[Anti-ballistic missile defense] constitutes a threat not only to the security of Russia, but to the whole world, in view of the possible destabilization of the strategic balance of powers."

"I believe this is dangerous for the U.S. itself, as it creates a dangerous illusion of invulnerability and reinforces the tendency of unilateral, often ill-considered decisions and additional risks," Putin said.

The missile shield is located on an old, 200-acre Romanian air base and will be manned by sailors rotating through for six months at a time. It will be equipped with a SPY-1 radar system and a vertical-launch missile system armed with long-range SM-3 missiles.

Much like the combat information center watch teams on surface combatants, the Aegis Ashore sites will be run round-the-clock by three crews.

Each shift has an 11-person watch team, including rates that typically work in a ship's combat information center: fire control technicians, operations specialists, and cryptologic technicians (technical). One watch officer will oversee them.

Officials plan to deploy three of these specially trained watch teams for six months at a time. This will be an operational tour, similar to a ship's cruise, and won't come with permanent change-of-station orders or the possibility of bringing dependents to Romania.

The deployment of long-range interceptors in Europe is part of the Obama administration's European phased adaptive approach to missile defense, announced in September 2009. The first phase involved forward deploying four destroyers to Rota, Spain, for rotating missile defense patrols.

The destroyer Porter arrived in Rota in April, and Carney will deploy there later this year. They join the Ross and Donald Cook already in country.