"This morning, Foreign Minister Wang Yi flew to Vienna to participate in the negotiations between Iran and the "six" [P5+1 negotiators]," Hua Chunying told reporters.
The spokesperson added that China is willing to play a constructive role in the negotiations.
"The talks have achieved a significant progress but differences still remain. It is an important time now for all parties to make a political decision, and we hope that all parties will stay focused and will move toward a comprehensive agreement."
In April, the P5+1 group reached a preliminary political framework agreement with Iran in Lausanne, Switzerland, which stipulated that Tehran cut back its uranium enrichment activities and decrease the number of centrifuges in exchange for gradual sanctions relief.
The deadline for reaching a comprehensive Iran nuclear deal was initially set for July 30, but as the date approached, the negotiators decided to extend talks until July 7.