The most recent letter late yesterday, from Mr. Jalili's deputy to Ashton's deputy, Helga Schmid, expressed "surprise" that Ms. Schmid's earlier letter "tabled issues that were a long way apart" from previous agreements and did not address Iran's counteroffer put forward in Baghdad in late May.
Jalili's deputy, Ali Bagheri, also asked why the P5+1 refused to meet at the experts level prior to the Moscow talks.
"If the agreements of each round of talks cannot be followed up at the level of deputies and experts, what guarantee will there be for the success of future talks?" Bagheri wrote in the letter that was leaked to Iranian media.
Diplomats from both sides claim that they have gone out of the way to accommodate the other in the interest of successful talks. But they also claim that they have "got nothing but some vague replies" (says the Iranian diplomat) or come up against "obfuscation" and "increasing negativity" (says a European diplomat in Brussels familiar with the talks).
In the past week there have been two direct calls between Bagheri and Schmid, notes the European diplomat. Since late May, five letters have been exchanged and "we have offered for at least a week a direct call between Ashton and Jalili, which they dragged their feet on."