US Defense Secretary Robert Gates said Friday that the new missile defense system planned for Europe has the flexibility to adapt to changes in Iranian missile capabilities even if US intelligence about Teheran's slower-than-expected pace proves wrong. US President Barack Obama's decision to scrap a Bush-era missile intercept system in Europe was based largely on a new US intelligence assessment that Iran's effort to build a nuclear-capable long-range missile would take three years to five years longer than originally thought, officials said earlier. Gates, a former CIA director, said that even if Iran should move more quickly on its long-range missile program, the revised program will have the flexibility to deal more quickly and effectively with the change. "We actually are better able to deal with a changed situation, in which the intelligence assessments are wrong, with the new architecture than we were with the old one," Gates told reporters. The new assessment asserts Iran is unlikely to have a nuclear-capable intercontinental ballistic missile until 2015 to 2020, a US government official familiar with the report told The Associated Press. The official spoke on condition of anonymity because the report remains classified. It is the second time in two years US intelligence has revised downward the threat posed by Iran's weapons programs. Obama abruptly canceled on Thursday a long-planned missile shield for Eastern Europe, replacing the Bush-era project that was strongly opposed by Russia with a plan the president contended would defend better against a growing threat of Iranian missiles. The United States no longer will seek to erect a missile base and radar site in Poland and the Czech Republic, virtually on Russia's doorstep. President George W. Bush contended that the missile base was needed to shoot down any Iranian missile if it ever developed one with adequate range to threaten the United States or Europe. The United States already has a similar missile site and radar in Alaska. Previous intelligence assessed that Iran would have an ICBM capable of menacing Europe and the United States between 2012 and 2015, another US government official said. The assessment changed because Iran has not been conducting the kind of observable development and testing that would be expected to accompany a robust long-range missile program, the second official said. The new assessment is contained in a classified May 2009 National Intelligence Estimate. The secret report is called "Foreign Ballistic Missile Development and Threat Through 2020." National Intelligence Estimates contain the consensus judgment of all 16 American intelligence agencies about critical national security issues. Thomas Fingar, former chairman of the National Intelligence Council, said Iran's progress, or lack thereof, on its ballistic missile program can be observed easily. "There's been a lot of testing. They learned from the tests and we learned from the tests," Fingar said. Fingar, who spearheaded the controversial 2007 national intelligence estimate that disclosed Iran had halted its nuclear weapon design work in 2003, was not privy to the new intelligence. But he said Iran may be working on short-range missiles because they are easier to build than large, long-range missiles, and lessons learned in their development can be applied to larger missiles. He also said Iran may not be aggressively pursuing an ICBM because it has discerned its most likely adversaries are in the region, so shorter missiles have more immediate utility for offensive attacks or deterrence. The new Obama plan would deploy systems designed to shoot down short- and medium-range missiles, with construction in phases to begin around 2011. Systems to counter longer-range missiles would be in place around 2020.