China said Thursday it hoped negotiations on Iran nuclear issue would be resumed at an early date and it would continue its efforts for this end.

"Dialogues and negotiations are the best ways to resolve this issue, " said Ma Zhaoxu, spokesman of the Foreign Ministry, at a regular press conference.

Ma also said "China is serious on safeguarding the effectiveness of the international system of nuclear non-proliferation".

He called for an early resumption of the peaceful negotiation, and said China would contribute to it.

Iran announced Tuesday it had started the process of producing 20 percent enriched uranium inside the country, provoking warnings by western countries of new sanctions.