An Iranian official said on Saturday that the country's leadership was determined to refuse the West's request for a halt of sensitive nuclear activities, the semi-official Mehr news agency reported.

"The West has raised two preconditions in a proposal -- freezing nuclear activities and responding to questions raised by the Board of Governors of the International Atomic Energy Agency (IAEA)," Abdolreza Rahmani-Fazli, deputy secretary of Iran's Supreme National Security Council, was quoted as saying.

"But our leadership has been determined that they would not accept the demands," he said.

The remarks were seen as an explicit rejection of the West's demands on Iran's nuclear program for the first time.

On June 6, EU foreign policy chief Javier Solana presented Iran with a package agreed on by the five permanent members of the UN Security Council plus Germany concerning the Iranian nuclear issue.

The proposal includes both incentives aimed at persuading Iran to suspend uranium enrichment and possible sanctions if Iran does not comply.

Western countries have been pressing Tehran to respond to the six-nation package before Saturday, but Iran has rejected the request.

The six countries agreed on Wednesday to return Iran's nuclear issue to the UN Security Council.

The move drew a strong reaction from the Iranian government. President Mahmoud Ahmadinejad warned on Thursday that his country would revise cooperation with IAEA and may quit the Non-Proliferation Treaty (NPT) if the West is not sincere on the nuclear issue