The negotiators had been discussing the implementation of a landmark interim accord agreed last month with the P5+1 – Britain, China, France, Russia and the United States, plus Germany.
"The Iranian negotiators interrupted the talks with the P5+1 for consultations in Tehran," a negotiator said on Thursday.
Under the interim deal reached in Geneva, Iran agreed to freeze parts of its suspect nuclear program for six months in return for some $7 billion in relief from Western sanctions as it negotiates a final, comprehensive accord to allay suspicions it is seeking a weapons capability.
The United States also agreed to refrain from slapping new sanctions on Iran, but senior administration officials argued that Thursday's measures were taken as part of the existing sanctions regime which had forced Tehran to the negotiating table.
MNA
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