The officials spoke on condition of anonymity because they were not authorized to discuss the matter by name. But, their comments were similar to a statement the State Department issued on Sunday.
The officials spoke after Iran's foreign ministry said earlier Monday that it would attend without preconditions.
In New York, Russia's U.N. ambassador Vitaly Churkin said "of course" both the U.S. and Russia were consulted about the Iran invitation, and he said that if the Syrian opposition boycotts the talks, "that would be a big mistake."
The invitation to Tehran from Secretary-General Ban Ki-Moon came after the U.N. chief said he had received assurances from Iran that it accepted the premise of the talks - to establish a transitional government for Syria, which has been led by the Assad dynasty since 1970.<