TEHRAN, Jan. 4 (Xinhuanet) -- Iran, a country accused by Washington of developing nuclear weapons secretly, remains tough and resolved on its nuclear fuel cycle program in defiance of EU warnings and Russia's compromise suggestion.

   Ali Larijani, Iran's chief nuclear negotiator, said on Wednesday that Tehran's decision to resume work on nuclear fuel research was "not negotiable."

   "We have stated that the research work is not included in the negotiations, and research is different from and has nothing to do with the actual industrial production," Larijani was quoted by the state television as saying.

   Larijani's remarks came one day after Mohammad Saidi, deputy chief of Iran's Atomic Energy Agency, announced that Iran had decided to resume research work on nuclear fuel in a few days.

   Saidi stressed that activities to be resumed were just related to research and had nothing to do with the actual production, noting that the research would be carried out under the supervision and cooperation of the International Atomic Energy Agency (IAEA).

   President Mahmoud Ahmadinejad said on Tuesday that Iran had informed the IAEA of the decision, adding that the Islamic Republic would "not retreat even one step" from its decision to resume the nuclear fuel work.

   IAEA Director General Mohamed Elbaradei on Tuesday reiterated the agency's position that it was important for Tehran to keep all work related to uranium enrichment suspended in order to remove suspicions of the international community over its nuclear program.

   The United States also urged Tehran to abide by agreements reached with the European Union.

   France and Germany, two members of the so-called European trio which has been negotiating with Iran on its nuclear program for more than two years, on Wednesday issued warnings that Iran's rigid mentality would have a negative impact on a new round of negotiations.

   French Foreign Ministry spokesman Jean-Baptiste Mattei said that Paris strongly called on Iran to draw back its decision because the resumption of fuel research would run counter to demands of the IAEA and impose serious doubts on the continuation of the negotiations.

   Mattei was echoed by his German counterpart Martin Jaeger, who warned that Iran's hardline decision had raised serious concerns and would endanger the talks with Europe.

   The European trio, with Britain as another member, is scheduled to hold a new round of negotiations with Iran on Jan. 18, expecting that Iran will accept a Russian proposal to conduct uranium enrichment activities in Russia.

   Last month, Moscow put forth its proposal to establish a joint venture in Russia to enrich uranium for Iran, but Tehran has rejected it as an immature structure which needs to be complemented and supported.

   A Russian delegation will arrive in Iran on Saturday to persuade the Islamic Republic on the proposal and Russia's nuclear chief is also set to visit Iran in February.

   However, Iran has posed an uncompromising stance on its position that uranium enrichment must be carried out in its own territory.

   Iran also announced on Sunday that it had developed a key technology to separate uranium from its ore with the so-called "mixer-settler," marking a significant step closer to the country's ambition to construct and run nuclear fuel cycle independently.

   Enriched uranium, a key material for nuclear fuel cycle, can also be used to build atomic bombs.

   The EU fears that Iran's complete command of uranium enrichment could lead to military purpose, while Tehran regards enrichment as an undeniable right enshrined in the Non-Proliferation Treaty. Enditem