Two days worth of negotiations last week in Kazakhstan concluded with few breakthroughs. Catherine Ashton, the foreign policy chief for the European Union, said both sides were "far apart" on the substance of the nuclear debate.
Iran is suspected of pursuing the technology needed to manufacture a nuclear weapon. The Iranian government denies the allegation, saying it has a right to a peaceful nuclear program as a party to the nuclear Non-Proliferation Treaty.
Director of the Atomic Energy Organization of Iran Fereydoun Abbasi said there are no plans for higher enrichment levels.
"At present, we have no enrichment plan for purity levels above 20 percent but when it comes to certain needs, for example, for some ships and submarines, if our researchers need to have a stronger underwater presence, we will have to make small engines which should be fueled by 45-56 percent enriched uranium," he was quoted by the semiofficial Fars News Agency as saying.
Iranian negotiators said last week that enrichment wasn't up for debate.
The International Atomic Energy Agency said in February that Iran had installed new uranium centrifuges at its Natanz nuclear facility. Western powers, however, say that could make it easier to reach the 90 percent purity needed for a nuclear weapon.