Iran's supreme leader Ayatollah Ali Khamenei has demanded concrete policy changes from the US as the price for new relations between the two states.

Ayatollah Ali Khamenei said he had seen no change in America's attitude or policy, singling out US support for Israel and sanctions against Iran.

But he also said that if President Barack Obama altered the US position, Iran was prepared to follow suit.

President Obama on Thursday offered "a new beginning" in relations with Iran.

He made the offer in a video message to Iran's leaders and people seen as a dramatic break with the approach of George W Bush's administration.

Relations between Iran and the US have been strained over Tehran's nuclear activities.

BBC Iranian affairs analyst Sadeq Saba says that a minimum requirement for Iran would be a move by Washington to ease US sanctions.

'Words not enough'

Speaking to a large crowd in the holy city of Mashhad, Ayatollah Khamenei said Iran had "no experience with the new American government and the new American president".