WASHINGTON (AFP/Reuters) - US President Barack Obama abandoned Thursday plans for a missile defense shield in the Czech Republic and Poland, replacing them with a revamped project after reassessing the threat from Iran. The dramatic foreign policy shift risked alienating US allies in the former Soviet bloc who were to host interceptor missiles and a radar base by 2012 but delighted Russia, the chief opponent of the plans. This new approach 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, Obama said in a brief statement. The decision followed a reappraisal that the threat was not so immediate from Irans long-range missiles, but was also grounded on advances in US missile defense technology, particularly with land and sea based interceptors. Our clear and consistent focus has been the threat posed by Irans ballistic missile program and that continues to be our focus and basis of the program that were announcing today, Obama said. His Defense Secretary Robert Gates fleshed out the new plans, saying interceptor missiles would initially be deployed on ships to make them more easily transportable from one region to another. The second phase, about 2015, will involve fielding upgraded land-based SM-3s. Consultations have begun with allies, starting with Poland and the Czech Republic, about hosting a land-based version of the SM-3 and other components of the system. The US will initially deploy Navy ships equipped with Aegis missile interceptors to help defend Europe and US forces against threats from Iran and others, Gates said. Gates said the Pentagon planned at a later phase to deploy land-based interceptors and was exploring the option of stationing some of them in the Czech Republic and Poland. He said Washington remained committed to defending Europe from missile threats. Those who say we are scrapping missile defense in Europe are either misinformed or misrepresenting the reality of what we are doing, he told reporters at the Pentagon Marine Corps General James Cartwright, vice chairman of the Joint Chiefs of Staff, said the Pentagon also envisioned eventually deploying a land-based radar as part of the system which would ideally be based in the Caucasus. Gates said the decision to change plans was based mainly on technological developments and a shift in intelligence assessments to meet short and medium-range missile threats posed by Iran. But he said the change should also address concerns voiced by Moscow, which vociferously opposed the previous plan. The Russians are probably not going to be pleased that we are continuing with missile defense efforts in Europe, Gates said. But, at the same time, there are two changes in this architecture that should allay some of their what we think (of as) unfounded concerns. Ships with Aegis interceptor systems are capable of blowing up ballistic missiles above the atmosphere. The system can track over 100 targets, military officials said. Cartwright said the Pentagon envisioned keeping three ships at any given time in and around the Mediterranean and the North Sea to protect areas of interest, with the possibility of surging additional ships to the region as needed. A second phase of the system, Gates said, involved deploying upgraded, land-based SM-3s starting in about 2015. We have now the opportunity to deploy new sensors and interceptors in northern and southern Europe that near term can provide missile defense coverage against more immediate threats from Iran or others, he said. Gates said consultations on deploying land-based SM-3s had begun with Poland and the Czech Republic. Obama had ordered a review earlier this year of deals signed last August by the previous administration of then president George W. Bush to build a radar station in the Czech Republic and install 10 interceptor missiles in Poland. Czech Prime Minister Jan Fischer said he was told in a late-night call from Obama that those shield plans had been scrapped and that Poland had been given a similar message. President Obama called me shortly after midnight to tell me his government was giving up its intention to build a radar base on Czech soil, Fischer said. The United States had used the threat from rogue states such as Iran to justify the shield, but the scheme had inflamed tensions between Moscow and Washington with Russia moving its own ballistic missiles in November to the Baltic Sea territory of Kaliningrad. We value the US presidents responsible approach towards implementing our agreements, Medvedev said in an address shown on national television. I am ready to continue the dialogue. We will have a good opportunity to exchange views on all aspects of strategic stability, including anti-missile defence. I believe that we will proceed with giving orders to the respective bodies in our two countries to step up cooperation, including on attracting European and other interested nations, he said of a meeting with Obama in New York on Sept. 23. Russia officials applauded the move to scrap the shield. German Foreign Minister Frank-Walter Steinmeier said, I am pleased that, after todays decision, we now have the possibility to again discuss the issue of missile defence in Europe with all partners. I have stressed from the outset: in the end we need more and not less collective security. Therefore, I have always been convinced that we must find common answers to common threats. Senior Iranian government Source said, There could be two reasons behind such a decision, either the U.S. has reached the conclusion that Iran is not a threat, or the Russians may have convinced the Americans there is no need for such defence shield. Czech President Vaclav Klaus said, This step by the U.S. government was no big surprise for anybody who had been following the cues in the past days and months. I am 100 percent convinced that this step by the American government is no expression of a cooling in relations between the United States and the Czech Republic. But the move drew fire in Poland and the Czech Republic, former Soviet bloc nations where the significance of the shield deal went far beyond the Iranian threat. Mirek Topolanek, who was prime minister when Prague agreed to co-host the shield, said a US decision to drop it is not good news for the Czech state, for Czech freedom and independence. In Poland, former president and Nobel laureate Lech Walesa said it might well be time for the nation to rethink its close relationship with the United States. Observing Obamas policy, I expected it, he said.