BEIJING -- Chinese Foreign Minister Wang Yi left Beijing to join negotiations on the Iranian nuclear issue in Vienna on Thursday.

"The Chinese side attaches great importance to advancing the negotiations on the Iranian nuclear issue," Foreign Ministry spokeswoman Hua Chunying said when announcing Wang's schedule for the foreign ministers' meeting of Iran and the P5+1, or five UN Security Council permanent members including Britain, China, France, Russia and the US, plus Germany.

China stands ready to work ceaselessly with all sides concerned to reach a comprehensive, impartial, balanced and win-win deal on the Iranian nuclear issue as soon as possible, said the spokeswoman.

Iran and the P5+1 have been engaged in intensive talks over Iran's nuclear program in recent months. After missing the June 30 deadline for a final deal, the two sides agreed Tuesday to extend the deadline to July 7.