Iran President Mahmoud Ahmadinejad said on Thursday that Tehran is ready to sit down with world powers for talks on its nuclear drive as he downplayed the harmful effects of newly imposed sanctions.

The Islamic republic, which was already under four rounds of United Nations sanctions, vehemently denies its nuclear programme masks an atomic weapons drive as the West alleges, and insists it is for civilian purposes only.

"They have this excuse that Iran is dodging negotiations while it is not the case," the Iranian leader was quoted as saying by state media.

"A person who has logic and has right on his side, why should (he) refrain from negotiations?"

He was implicitly responding to comments made by Western officials urging the Islamic republic to return to negotiations over its contested nuclear programme.

The last round of talks between Iran and the major powers consisting of Britain, China, France, Germany, Russia and the United States was held in Turkey in January 2011, but the negotiations collapsed.

EU foreign policy chief Catherine Ashton said on Tuesday: "The European Union stands together in sending that clear message to the government of Iran: that we wish to go back to negotiations, to invite them to pick up the issues which were left on the table in Istanbul a year ago."

The six powers are still waiting for Iran's reply to a letter Ashton sent in October, stressing that negotiations should focus on the "key question" of the Iranian nuclear issue, in order to remove doubts.

The United States declined to directly respond to Ahmadinejad's comments Thursday, saying instead that Tehran should formally reply to Ashton's letter.

"Our position is that it is as it always has been -- the Iranian regime needs to live up to its obligations to the international community," White House spokesman Jay Carney told reporters aboard Air Force One.

In Washington, State Department spokeswoman Victoria Nuland said the letter "very specifically offers talks if Iran is ready to be serious about coming clean with regard to its nuclear programme".

"So just saying you're open for talks doesn't meet the criteria that we have set, which is to be ready for talks and ready to be serious about letting the world know all of the details of your nuclear programme and proving your claims that it's for peaceful purposes."

Several Iranian officials have said publicly that Tehran was ready to resume talks, but without specifying the content of the talks, and have not yet formally responded to Ashton's letter.

"Iran is ready to negotiate on the basis of mutual respect," Iran's Foreign Minister Ali Akbar Salehi said on Wednesday.

He said he would forward the response from Iran's top nuclear negotiator, Saeed Jalili, "on the date and place of negotiations," to his Turkish counterpart Ahmet Davutoglu, who is acting as an intermediary, to be given to Ashton.

The European Union on Monday slapped an embargo on Iranian oil imports as the West ramped up the pressure.

In his televised comments, Ahmadinejad brushed off the effects of the newly imposed sanctions, saying they would not hurt his nation.

"Once our trade with Europe was around 90 percent but now it has reached 10 percent and we are not seeking this 10 percent... Experience has shown that the Iranian nation will not be hurt," Ahmadinejad said during a visit to the southern Kerman province.

"For the past 30 years, the Americans have not been buying oil from us. Our central bank has no relations with you."

Iranian media reported that parliament would consider a bill next week to ban oil exports to Europe following the bloc's decision to impose an embargo.

EU foreign ministers agreed on an immediate ban on oil imports and a phase-out of existing contracts up to July 1. They also froze the assets of Iran's central bank while ensuring legitimate trade under strict conditions.

The bloc imported some 600,000 barrels per day of Iranian oil in the first 10 months of last year, making it a key market alongside India and China, which has refused to bow to pressure from Washington to dry up Iran's oil revenues.

The new EU sanctions would make it even more difficult for Iran to be paid in foreign currency for its oil exports, which were worth more than $100 billion in 2011.