DUBAI - Iran has confirmed it tested a new centrifuge that could speed up its enrichment of uranium but dismissed suggestions the move may have violated last year's nuclear deal with world powers, as suggested by a US think-tank.Foreign Ministry spokeswoman Marzieh Afkham gave no indication that Iran had stopped feeding natural uranium gas into the so-called IR-5 centrifuge. Washington said on Monday Tehran had ceased the activity.Iran's development of advanced enrichment centrifuges is sensitive because, if successful, it could enable the country to produce potential nuclear bomb material at a rate several times that of the decades-old model now in use. Iran says it is only producing enriched uranium to fuel nuclear power plants.Afkham said the IR-5 was among ordinary machines belonging to Iran's Atomic Energy Organization, the official state news agency IRNA reported."Such tests were conducted before the Geneva agreement (between Iran and the world powers) and have continued after the deal was reached," she said late on Tuesday. "Testing on the machines will be carried out and stopped depending on the need."