Iranian president Mahmoud Ahmadinejad's letter to his American counterpart might create a new diplomatic opening, but did not indicate Iran had softened its stance, Iran's chief nuclear negotiator said in Tehran on Monday.

In an interview with Turkey's private NTV television channel, Ali Larijani, who is on a visit to Turkey, declined to give details of the letter, but said "perhaps it could lead to a new diplomatic opening."

The letter was delivered to U.S. President George W. Bush by the Swiss embassy to Iran, Iranian government spokesman Gholam Hossein Elham said on Monday.

President Ahmadinejad, who has vowed never to give up right to peaceful nuclear technology, proposed new solutions to the international problems in the letter, the spokesman said.

The White House said on Monday that it was unaware of a letter from Ahmadinejad to Bush, the first from an Iranian president to his American counterpart in 27 years.

Larijani arrived in Ankara on Monday morning to seek support for its nuclear position as the UN Security Council is considering a draft resolution presented by Britain and France that obliges Iran to freeze all uranium enrichment activities or face sanctions.

Larijani also warned against any U.S. attack on Iran, saying that "Iran is not Iraq. Iran is a powerful country."