China believes diplomatic efforts have not yet been exhausted and calls for further dialogue and negotiation to resolve the Iran nuclear issue, Foreign Ministry spokesman Qin Gang said?on Thursday afternoon.

At a routine press briefing, Qin said there is still room for dialogue and negotiation to resolve the Iran nuclear issue. He called on all parties to consider the overall situation, strengthen communication, and maintain the momentum of dialogue and negotiation to achieve a peaceful solution.

Qin's remarks came after the U.S. government Wednesday threatened to push for tougher sanctions on Iran in the UN Security Council.

U.S. Secretary of State Hillary Rodham Clinton on Wednesday said, "Iran has left the international community little choice but to impose greater costs for its provocative steps."

In response to a question, Qin said the key to easing the Iran nuclear issue lies in promptly settling the issue of fuel supply to Tehran's research nuclear reactor.

Moreover, Qin said, it is important the six relevant countries resume talks with Iran as soon as possible. The six countries are the five permanent members of the UN Security Council, namely the United States, Russia, Britain, France and China, and Germany.

Qin said China will maintain communication and coordination with all parties concerned and play its proper role in the process.

Iran announced earlier this week a plan to build two additional uranium enrichment plants in coming months. Iran insists on its right to developing nuclear technology for peaceful purposes.

Iranian President Mahmoud Ahmadinejad said in November Iran will build 10 new uranium enrichment plants to meet the nation's growing energy needs.