BEIJING -- China on Thursday called on relevant parties to enhance diplomatic efforts in resolving the Iranian nuclear issue after Iran's atomic chief said nuclear fuel swap talks were over.

"Under the current circumstances, relevant parties should ratchet up diplomatic efforts, continue to commit to dialogue and negotiation, take new measures to deepen trust, and create new conditions to properly resolve the Iranian nuclear issue," Foreign Ministry spokesperson Ma Zhaoxu said at a regular briefing on Thursday.

Ma's comments came days after Fereydoun Abbasi-Davani, vice president and head of the Atomic Energy Organization of Iran, said Iran will no longer negotiate a nuclear fuel swap with some world powers and will not stop producing uranium at a 20 percent level of enrichment for the Tehran reactor.

As a signatory of the Nuclear Non-Proliferation Treaty (NPT), Iran has the right to peacefully utilize nuclear power and assume due international obligations, Ma said.