A new article has shed light on some disagreements within the US State Department regarding the Iran policy and the US negotiating team in Vienna.

The Al-Arabia article published on Thursday cited US diplomats and sources close to several former and current officials that there is a growing frustration within the State Department due to the centralized decision-making in the hands of only a few officials.

At least three members of the Iran negotiating team, which Special Envoy Robert Malley leads, have left in recent months, namely Richard Nephew, Ariane Tabatabai, and Dan Shapiro.

Nephew, who is known as the architect of Washington’s sanctions against Iran, left his position as the deputy to Malley on December 6 but in January he announced that his decision was “due to a sincere difference of opinion concerning policy.”

According to Al-Arabia sources, Tabatabai decided to leave the team because Malley allowed Russia’s ambassador in Vienna to take the lead on the talks, and Shapiro, a former US ambassador to Israel, also left his role as a senior advisor to Malley after about seven months. The unnamed sources said there was dissatisfaction among the negotiating team over Malley’s unwillingness to listen to opposing points of view.

Nephew told Al Arabiya that he will not comment about the Vienna talks “out of respect for the fact that the negotiations are ongoing and any public comments that I might make could unfairly prejudice those talks or affect the US position.”