WASHINGTON (CNN) - The United States is dropping plans for a controversial missile defense shield and replacing it with a "new missile defense architecture in Europe," President Barack Obama said Thursday.
The new system "will provide capabilities sooner, build on proven systems and offer greater defenses against the threat of missile attack than the 2007 European missile defense program" proposed by former President George W. Bush, Obama said.
He did not go into details about the new plan, but said it had received the unanimous support of Defense Secretary Robert Gates and the Joint Chiefs of Staff.
Obama said the change of gears was based on an "updated intelligence assessment" about Iran's ability to hit Europe with missiles.
The Islamic republic's "short- and medium-range" missiles pose the most current threat, he said, and "this new ballistic missile defense will best address" that threat.
Defense Secretary Robert Gates, speaking from the Pentagon immediately after the president's announcement, denied the United States was "scrapping" missile defense.
"This new approach provides a better missile defense capability for our forces in Europe, for our European allies and eventually for our homeland than the program I recommended almost three years ago," he said. Gates served as secretary of defense in the last two years of the Bush administration, and stayed on in the post when Obama took office.
The Bush-era proposal called for the United States to set up a radar site in the Czech Republic and 10 missile interceptors in Poland to counter the threat of Iran launching long range missiles at America's allies in Europe.
The Bush administration had cited the perceived nuclear threat from Iran as one of the key reasons it wanted to install the missile shield in eastern Europe.
But a 60-day review mandated by Congress and ordered by Obama recommended a different approach, a senior administration official said before the president and Gates spoke.
"The technology has evolved in a way that allows you to deploy a system that is more effective in countering both short, medium, and long-range missiles," said the official, contrasting the types of missiles Iran, for example, is believed to have with intercontinental ballistic missiles of the kind feared during the Cold War.
"It's a more advanced system, more cost effective and efficient," the official said.
The U.S. reversal is likely to please Russia, which had fiercely opposed the plans.
There was no comment Thursday morning from Russian officials. But the issue has been a sore point in relations between Washington and Moscow, with Russia believing the shield would ultimately erode its own strategic nuclear deterrent.
Obama has been seeking a stronger relationship with Russia and better cooperation from the Kremlin to support tough U.N. economic sanctions against Iran if it continues to pursue its nuclear ambitions.
Obama and Russian President Dmitry Medvedev discussed the missile shield, among other issues, in Moscow in July.
Obama maintained that Russia had nothing to fear from such a system, which would be designed to intercept a solitary missile from Iran or North Korea, as opposed to "a mighty Russian arsenal."
But the senior administration official flatly denied a diplomatic motive to scrapping the missile defense program.
"This has nothing to do with Russia," he said. "The notion that we're
abandoning missile defense is completely false. It's evolving into a different system."
A U.S. delegation held high-level meetings Thursday in both Poland and the Czech Republic to discuss the missile defense system. While the outcome of the meetings wasn't clear, officials in both countries confirmed the plans for the current system would be scrapped.
Czech Prime Minister Jan Fischer said in a statement that Obama told him in a Wednesday phone call that the United States was shelving its plans. Fischer did not say what reason Obama gave him for reconsidering.
A spokeswoman at the Polish Ministry of Defense also said the program had been suspended.
"This is catastrophic for Poland," said the spokeswoman, who declined to be named in line with ministry policy.
Poland and the Czech Republic had based much of their future security policy on getting the missile defenses from the United States. The countries share deep concerns of a future military threat from the east - namely, Russia - and may now look for other defense assurances from their NATO allies.
"At the NATO summit in April, we adopted a resolution focusing on building a defense system against real, existing threats, i.e. short-range and medium-range missiles," Fischer said. "We expect that the United States will continue cooperating with the Czech Republic on concluding the relevant agreements on our mutual (research and development) and military collaboration, including the financing of specific projects."
- CNN's Suzanne Malveaux in Washington, Per Nyberg in London, England, and Matthew Chance in Moscow, Russia, contributed to this report.