This was reported by The Wall Street Journal, citing sources.
As noted, disagreements in the American delegation arose around how tough a position should be taken in the negotiations.
According to the publication, in the current situation, three supporters of a tougher position refused to participate in the work and left the negotiating team.
Earlier, the State Department said that progress in the negotiations on the JCPOA was modest, and called for a more serious approach to this issue.
On January 20, Russian Foreign Minister Sergei Lavrov and Iranian Foreign Minister Hossein Amir Abdollahian discussed the "nuclear deal".
It is noted that “both sides confirmed their intention to continue negotiations in Vienna in order to restore the “nuclear deal” in its original configuration, without any “add-ons” and exemptions.”