COPENHAGEN/TEHRAN (AFP/Reuters) - Iranian President Mahmoud Ahmadinejad accused Barack Obama of following the footsteps of George W Bush since entering the White House, saying he had missed a chance to make a clean break. The head of Irans Atomic Energy Organisation told the Fars news agency on Friday the Islamic Republic plans to introduce its new generation of uranium enrichment centrifuges by March 2011. Ahmadinejad, in Copenhagen for a UN climate change summit, said he had welcomed the slogans of change when Obama was elected US President a year ago but he had not lived up to expectations. He has not used the possibilities, making decisions similar to the previous (Bush) administration, he told a Press conference. We see they are sending more troops to Afghanistan, thats a continuation of the policy of the former administration and the situation has not changed in Iraq and Palestine, he added. Ahmadinejad said there were many politicians in the US who see themselves as the masters and owners of the world, adding that Obamas behaviour had made us concerned. In remarks published by the semi-official Fars news agency on Friday, the head of Irans Atomic Energy Organisation, Ali Akbar Salehi, told the Fars news agency on Friday that Iran expected to be using a new generation of nuclear centrifuges, which it has been testing for about two years, for full-scale uranium enrichment by March 2011. We are producing new generation of centrifuges named IR3 and IR4 ... We plan to use them by 2011 after eliminating problems and defects, Salehi told Fars. Enriched uranium can be used to fuel nuclear power plants and, if refined further, provide material for atomic bombs. Salehi said Iran now had over 6,000 active centrifuges. We prefer to buy fuel for our reactor ... deadlines cannot be set for an independent country like Iran, Salehi told the student news agency ISNA. In a report last month, the UN nuclear agency said 3,936 centrifuges were enriching uranium at Natanz, a 15pc drop from February, while another 4,756 were installed but were not producing enriched uranium. Analysts said Iran seemed to be having technical problems, but Iran says it will not shelve its enrichment activities. The new machines dont have the vibration or breakage problems of the P-1. Iran has had trouble running the P-1s at full speed, said David Albright of the Institute for Science and International Security, a Washington think tank which tracks nuclear proliferation. We think they have a lot of broken P-1s. Iran may have decided they cant solve the P-1s problems and thats why they are announcing this today, he told Reuters. They would have every incentive to move up to IR2s, IR3s and so on. On balance, this is troubling news.