World powers convene once again in Vienna on Tuesday, set to begin drafting a comprehensive treaty with the intention of ending international concerns with Iran's nuclear work.
Yet just as political directors from Iran, the United States, United Kingdom, France, Russia, China and Germany arrived in Austria for the talks, a confidential United Nations report leaked accusing Iran of expansive efforts to circumvent UN-backed sanctions.
Also preceding the talks, a meeting on Monday between Iranian officials and the International Atomic Agency - tasked with enforcing an interim deal between the parties temporarily freezing the crisis, and any future comprehensive agreement - ended with silence from both sides.
The IAEA has demanded Iran take several practical steps before May 15 in order to demonstrate compliance with its international obligations. At the moment, the UN body seeks clarification on fast-acting detonators obtained by Iran that can have both military and civilian applications.
Iran says it is in full compliance with the interim agreement reached last fall in Geneva.
Meanwhile, the confidential UN report highlights Iran's methods of evading financial penalties and restricted imports - from concealing titanium tubes inside steel pipes to using its petrochemical industry as a cover to obtain items for a heavy-water nuclear reactor.
The latest report by the UN Panel of Experts, which monitors ​compliance with the ​Security Council's sanctions regime on Iran, said Tehran's attempts to illicitly procure materials for its disputed ​ ​ nuclear and missile program may have slowed down as it pursues ​ ​ talks on a long-term deal with world powers.
But the experts' report, which reached the Security Council's Iran ​ ​ sanctions committee days ahead of a new round of Vienna talks between Iran and six world powers, said an alternative explanation could be ​that Tehran had merely learned how to outsmart security and​ intelligence services in acquiring sensitive components and materials.
One example of concealment given by the panel's report was a set of titanium tubes hidden inside a shipment of stainless steel pipes ​manufactured in and shipped from ​China. The pipes were ordered by Ocean ​Lotka International Shipping and Forwarding Co. on Valiasr St. in​ Tehran.
Despite concerns from the UN agencies, negotiations were to continue as planned in Vienna, where the parties expressed optimism that the first phase of drafting could begin.
​State Department deputy spokeswoman Marie Harf said last week that the US was "absolutely" comfortable with beginning the drafting process.
"We do feel like we can start drafting and do feel like we can get this done by July 20 ​," she said, referring to a self-imposed deadline for the end of negotiations.​ ​"​We don’t know if we will, if we’ll all be able to, but we think we can."
​"​Under Secretary for Political Affairs Wendy Sherman, the Obama administration's chief negotiator ​in the Iran talks, first traveled to Brussels for initial consultations. Sherman also traveled to Israel last week with National Security Advisor Susan Rice briefing Prime Minister Benyamin Netanyahu, and his ministers, on the progress of the negotiations.