UPDATED 17:27 PM EST, January 25, 2013
Negotiations had been envisioned for next week. But State Department spokeswoman Victoria Nuland says the U.S. and its partners have been "surprised that the Iranians keep coming back again and again with new preconditions, new dates and venues."
She says consultations with Iran continue on finding a city and date for a meeting.
The U.S. complaint echoes that of the European Union, which suggested earlier this week that Iran was willfully delaying the talks.
