The White House on Friday admitted that the chances of reaching a deal to curb Iran's nuclear program were only 50 percent, AFP reported.
White House spokesman Josh Earnest said: "The likelihood of success in these diplomatic talks are at best 50/50."
The comments come as U.S. Lawmakers from both parties vowed at a Senate hearing on Wednesday to press ahead with legislative plans for new punitive measures against the Iranian regime if no deal on nuclear issue is achieved.
Democratic lawmaker Robert Menendez said during the Senate Foreign Relations Committee hearing: "The more I hear from the administration and its quotes, the more it sounds like talking points that come straight out of Tehran.
"And it feeds to the Iranian narrative of victimization when they are the ones with original sin."
Meanwhile, the nuclear talks between the Iranian regime and the U.S. resumed in Switzerland on Friday.
Two days of meetings between the Iranian regime’s deputy foreign minister Abbas Araghchi and top US negotiator Wendy Sherman began Friday morning in Zurich, a US spokesman told AFP.
US Secretary of State John Kerry, who met last week in Geneva and then again in Paris with his Iranian counterpart Mohammad Javad Zarif to discuss the nuclear negotiations, also returned to Switzerland Friday.