VIENNA, Nov. 24 -- Progress made in the Iran nuclear talks has laid a solid foundation for reaching a final deal over the Iranian nuclear issue, and China is optimistic about the prospect of the negotiations, said Chinese Foreign Minister Wang Yi on Monday.

He made the remarks after negotiators from Iran and the P5+1 group -- the United States, Britain, France, China, Russia and Germany -- concluded days of intensive talks in the Austrian capital. The parties have decided to extend the nuclear talks until the end of June next year.

Wang said foreign ministers from Iran and the P5+1 group agreed that important progress has been achieved so far in nuclear negotiations.

The Iranian nuclear issue is very complicated, and detailed calculations by experts are required as the issue involves many technical details, said Wang, adding that a lot of concrete work still needs to be done as a support even if political agreement has been reached.

Noting that no concrete deal is sealed during this round of talks due to limited time, Wang said all sides have expressed willingness to maintain the current momentum and continue with the talks, so as to reach a mutually-acceptable, comprehensive deal within the next few months to settle the nuclear issue.

As an important negotiating party, Wang said China holds a fair and objective stance in the nuclear negotiations, and has played a constructive role by bringing suggestions to the talks, including ideas presented Monday for resolving the remaining major problems.

He also urged all parties concerned to keep their determination to reach a final deal through joint efforts, adhere to the existing consensus of maintaining the international nuclear non-proliferation regime, meet each other halfway and show flexibility, so as to reach an agreement that can be accepted by all sides.