VIENNA - Iran, facing sanctions that could cripple its oil exports, has told world powers it wants to resume long-stalled talks with "new initiatives", and France said it might be open to addressing suspicions about its nuclear program.Tehran made the offer in a letter to the EU's foreign policy chief obtained by Reuters on Thursday, a day after it trumpeted several advances in nuclear know-how and sent oil prices upward.Iran's president vowed no retreat from its nuclear program on Wednesday but state television announced the proposal to re-launch talks after a year's hiatus.Iranian chief negotiator Saeed Jalili's letter said he would have "new initiatives" but did not spell them out. He made one reference to "Iran's nuclear issue", without spelling out whether Tehran was prepared to negotiate on it.French Foreign Minister Alain Juppe said that while the letter was "ambiguous" it seemed to signal "the start of opening up from Iran" with respect to discussing its nuclear activity.A Feb. 20-21 visit to Iran by top UN nuclear watchdog officials would help determine whether Tehran was serious about tackling international concerns, Juppe told reporters.The UN team, led by the International Atomic Energy Agency's chief inspector, will again try to extract Iranian explanations, after three years of stonewalling, for an IAEA investigation driven by intelligence reports that suggest Tehran has researched sophisticated ways to build atomic bombs.Jalili's letter was a reply to one from Ashton in October in which she said the big powers could meet with Iran within weeks if it was ready to "engage seriously in meaningful discussions".Jalili said he welcomed an earlier statement by Ashton on respecting Iran's right to the peaceful use of nuclear energy."(A) constructive and positive attitude towards the Islamic Republic of Iran's new initiatives in this round of talks could open positive perspective for our negotiation," Jalili said in the brief English-language letter."Therefore...I propose to resume our talks in order to take fundamental steps for sustainable cooperation in the earliest possibility in a mutually agreed venue and time."Jalili urged a focus "on a spectrum of various issues" to lay groundwork for "constructive, forward-looking cooperation".