An Iranian official says his country will not freeze its uranium enrichment programme in exchange for a pledge of no new UN Security Council sanctions.
Keyvan Imani's comments cast doubt on the success of talks between senior envoys from Iran and the six countries trying to persuade it to compromise on its nuclear programme.
The six nations hope Iran will agree to stop expanding its uranium enrichment programme. In exchange, they offer to hold off pushing for new UN Security Council sanctions against the Islamic Republic.
But Imani, speaking to reporters shortly after the talks began today, said there was "no chance" Iran would suspend enrichment.
For the first time, there is a senior US diplomat at the talks. The presence of Undersecretary of State William Burns had led to hopes Iran would compromise on suspension.
If there were agreement on the so-called freeze-for-freeze," the next step would be formal negotiations that the six nations hope will result in Tehran fully scrapping its enrichment activities in exchange for a package of political and economic incentives.
Enrichment can make either nuclear fuel or the material used in the fissile core of warheads.