Visiting Chinese Assistant Foreign Minister Ma Zhaoxu on Monday called on related parties to restart talks over Iran's nuclear issue as soon as possible.

Ma, who started a two-day visit to Iran on Sunday, held talks with Saeed Jalili, Secretary of Iran's Supreme National Security Council (SNSC) and chief nuclear negotiator, Ali Baqeri, deputy secretary of SNSC, and Iranian Deputy Foreign Minister Akhundzadeh Basti.

The two sides had intensive bilateral talks and exchanged views on Iran's nuclear issue in a candid and in-depth way.

Faced with the complicated situation surrounding Iran's nuclear issue, the concerned parties should work closely with each other and insist on solving the issue through dialogue and cooperation, Ma said when meeting with Iranian officials.

The most urgent issue is to restore nuclear talks between the six nations -- Britain, China, France, Russia, the United States and Germany -- and Iran as early as possible, and enhance cooperation between Iran and the International Atomic Energy Agency (IAEA), in a bid to find effective ways to solve the nuclear issue, Ma said.

Ma further said that China hopes Iran to answer EU (the European Union) Foreign Policy chief Catherine Ashton's letter to the Islamic Republic soon.

Iranian officials said Tehran agrees to restart nuclear talks with related parties, cooperate with the IAEA, and hold a new round of "fruitful" negotiations over its nuclear program.

Iran is ready to have serious negotiations with the above- mentioned six nations, and will respond to Ashton's letter soon, said Iranian officials.

Ma told reporters on Monday when wrapping up his visit that his talks with the Iranian side have been helpful, positive and constructive.

Iranian officials' remarks are significant positive signals, and China urges the concerned parties to snap up this opportunity, work concertedly and strengthen communication and coordination, in order to restore the nuclear talks as soon as possible, Ma said.

China, like in the past, will make every effort to promote dialogue, and play a positive and constructive role in helping a peaceful solution to the Iranian nuclear issue.