UPDATE 1-US actions contrary to desire for better ties-Iran

* Khamenei says U.S. desire for friendship not serious

* Khamenei avoids direct reference to Obama's speech

* Says those backing protesters wanted civil war

(Adds quotes, background)

TEHRAN, March 21 (Reuters) - Iran's Supreme Leader Ayatollah Ali Khamenei said on Sunday that Washington's actions contradict its call for friendly ties, a day after a renewed offer of dialogue by U.S. President Barack Obama.

Iran's most powerful figure made no direct reference to Obama's call on Saturday for dialogue with Tehran, which Washington and its allies suspect is trying to develop nuclear weapons under the cover of its atomic energy programme.

"The new administration and president claimed interest in just and fair relations, they wrote letters and sent messages ... saying they are willing to normalise relations with the Islamic Republic, but in practice they did the opposite," he said in an address in the holy city of Mashhad on the occasion of the Iranian New Year. It was carried by state television.

A year ago, Obama marked the Iranian New Year with an unprecedented message offering Iran a "new beginning" of diplomatic engagement with the United States.

Tehran rebuffed the gesture and relations soured further when Iranian authorities cracked down on opposition protesters after a disputed election last June.

But Obama nevertheless renewed the offer on Saturday.

"We are working with the international community to hold the Iranian government accountable because they refuse to live up to their international obligations," Obama said in an address released by the White House for Iran's New Year which begins on March 21.

"But our offer of comprehensive diplomatic contacts and dialogue stands," he said.

Khamenei cited U.S. policy on the opposition protests as an indication of unfriendly intentions.

"Eight months after the elections they took the worst possible stance. The president called those rioters and saboteurs 'civil rights activists'," he said in the speech. "Sometimes the U.S. government appears as a wolf or a fox and looks violent and arrogant, and sometimes they look different."

Khamenei said Iran's enemies had tried and failed in an effort to create civil war through backing opponents of the vote which returned hardline President Mahmoud Ahmadinejad to power.

"They hoped to create a civil war in this country but the people were vigilant ... It was a great ordeal and lesson and the people of Iran emerged victorious," he said.

Obama has pledged to pursue aggressive sanctions to prevent Iran from getting a nuclear weapon. He said in his address Washington was committed to a better future for Iranians despite U.S. differences with Tehran.

Obama's openness to engaging diplomatically with Iran if it "unclenched its fist" -- the phrase he used last year -- broke with the previous administration's policy of seeking to isolate the Islamic Republic, which President George W. Bush branded part of an "axis of evil." (Reporting by Andrew Hammond and Ramin Mostafavi; Editing by Jon Hemming)