By David Brunnstrom and David Alexander
BRUSSELS (Reuters) - The United States and Spain announced an agreement on Wednesday to base U.S. anti-missile warships at Rota on the Spanish coast, strengthening U.S.-led plans for a NATO-wide missile defense system in Europe.
The deal is part of U.S. President Barack Obama's so-called phased adaptive approach to missile defense, which calls for an initial deployment of ship-based anti-ballistic missiles in the Mediterranean followed by ground-based systems in Romania, Poland and Turkey.
The system is expected to start operating from next year and become fully operational in 2018. It is designed to protect European NATO states and the United States from missile attack from countries such as Iran and North Korea, which are developing longer-range missiles.
North Korea has a nuclear arms program and the West fears Iran is developing nuclear weapons. Tehran denies this.
The new agreement was formally announced at NATO headquarters in Brussels by Spanish President Jose Luis Rodriguez Zapatero, NATO Secretary-General Anders Fogh Rasmussen and U.S. Defense Secretary Leon Panetta.
"This commitment to collective defense is also a guarantee to the defense of Spain and Spaniards," Zapatero told a media conference. He said it would also be good for the economy of the Cadiz region of southwestern Spain where Rota is located.
Panetta said the deal would involve the stationing of four Aegis destroyers in Rota and Zapatero said this would generate about 1,000 jobs, given the need for investment in infrastructure, contracts with service firms and shipyards and the presence of some 3,000 U.S. personnel and their families.
Rasmussen called the missile defense project a success story of NATO's bid to encourage "smart defense" -- multinational collaborative projects that make best use of scarce resources.
Panetta said Spain's agreement to provide the base was "critical" for the missile defense project and showed the continued U.S. commitment to Europe despite massive defense budget cuts in the United States.
"This announcement should send a very strong signal that the United States is still continuing to invest in this alliance and that we are committed to our defense relationship with Europe," he told the briefing.
"The United States is fully committed to building a missile defense capability for the full coverage and protection of all of our NATO European populations, their territories and their forces against the growing threat posed by ballistic missiles."
Rasmussen said he "would not be surprised" if there were further announcements in the coming weeks and months on new contributions to the missile defense system.
A senior NATO diplomat said this week that the Netherlands had just announced plans to upgrade radars that would provide information for the NATO system.
The Obama administration launched the phased adaptive approach to missile defense in 2009 and abandoned former President George W. Bush's plan to build a land-based missile defense system in Poland and the Czech Republic.
The decision helped to reduce friction with Russia, which NATO has invited to join the project, although Moscow remains concerned that the system will reduce the deterrent value of its nuclear arsenal.
A senior U.S. defense official said making the base at Rota, on Spain's southwestern Atlantic coast near Cadiz, would reduce the numbers of ships needed for the system.
"You probably need 10 of these ships if they were based in the eastern U.S. to be able to ... transit across the ocean back and forth to patrol in the Med," he said.
The U.S. official said the United States was committed to having at least one ship on station at all times in the eastern Mediterranean, where their anti-missile missiles would be most effective. Having them based in Rota would enable more than one to be in the eastern Mediterranean as needed.
The ships also would be part of the pool of vessels available to participate in standing NATO maritime groups, which are used to counter piracy and for other missions, he said.
(Editing by Louise Ireland)