VIENNA, May 16 (Xinhua) -- The Iranian nuclear talks has already enter a "deep-water zone", thus the negotiation is like "crossing a river by feeling the stone," said China's chief negotiator in Vienna on Friday.
Wang Qun, head of China's delegation, director general of Chinese Foreign Ministry's arms control and disarmament department, made the remarks on Friday in Vienna after he met with Iranian delegation in Vienna.
Iran and five Permanent Members of the UN Security Council(China, France, Russia, the UK and the United States) plus Germany, so called P5+1 group, has held the forth round of talks in the capital city of Vienna.
When asked about the if any progress were made in the talk, he stressed the importance of this round of talks is to deepen the understanding of the sides on the substantive issues in this process.
Western countries want Iran to significantly scale back its nuclear program to address their concerns.
Since Iranian President Hassan Rohani took office last year, Iran promised to provide greater transparency to address western concern, hoping to resolve the issue through diplomatic channel.
Under the Geneva deal made in last November, Iran suspends some of its nuclear activities while western states relief some relevant sanctions in return.