Some elements of a permanent accord aimed at limiting Tehran’s nuclear program could be agreed during an upcoming round of Vienna talks between six world powers and Iran by May 16, Russia’s Deputy Foreign Minister Sergei Ryabkov said Tuesday, May 6, according to RIA Novosti.

“By the end of this round we should, at least, agree some elements of a coordinated text and details of a general text [of a final document],” Ryabkov said in an interview with RIA Novosti.

The latest round of talks, conducted at the political directors’ level between the governments of Iran and the P5+1 powers – the United States, United Kingdom, France, China, Russia and Germany – is due to start on Tuesday in Austrian capital, Vienna.

The fourth round of the P5+1 and Iran will be held in Vienna on May 13-16.

He said that issues related to details of inspections by the International Atomic Energy Agency (IAEA) and future limitations on Iran’s nuclear activities were hardest to agree.

Last month, a report issued by the International Atomic Energy Agency (IAEA) confirmed that Iran has neutralized half of its enriched uranium stockpile. In February, the IAEA reported that Iran’s stockpile of partially-enriched uranium hexafluoride dropped to 160 kilograms, a reduction of almost 20 percent. The West in return eased certain economic sanctions against Teheran.