Vienna, Austria ? Iran called Wednesday for talks with the United States – but despite a U.N. Security Council deadline did not budge on council demands that it mothball its uranium enrichment program or face harsher sanctions.

Amid Iran’s nuclear defiance, the U.N. nuclear watchdog finalized a report to be released today that is expected to formally confirm the Islamic republic’s refusal to freeze enrichment – a conclusion that could subject it to tougher U.N. sanctions.

Officials at the International Atomic Energy Agency said the report by Mohamed ElBaradei, head of the Vienna-based U.N. agency, would say Iran has expanded enrichment efforts instead of freezing them.

Once released, the report will be sent to the agency’s 35-nation board and to the Security Council, which set a deadline of Wednesday for a freeze and said Iranian defiance could lead to sanctions in addition to those imposed in December.

In remarks directed at Washington – the key backer of tougher U.N. action – Iranian Foreign Minister Manouchehr Mottaki said Wednesday the dispute “has to be decided peacefully with the United States.”

But other top Iranian officials used harsher language and none showed signs of compromise on the main demand of the U.S. and other world powers – a halt to enrichment and related activities.

“The enemy is making a big mistake if it thinks it can thwart the will of the Iranian nation to achieve the peaceful use of nuclear technology,” Iranian state TV’s Web site quoted President Mahmoud Ahmadinejad as saying. On Tuesday, he said Iran was ready to halt its enrichment program, but only if Western nations do the same.

The White House dismissed Ahmadinejad’s call.

“Do you believe that’s a serious offer?” White House press secretary Tony Snow asked. “It’s pretty clear that the international community has said to the Iranians, ‘You can have nuclear power but we don’t want you to have the ability to build nuclear weapons.’ And that is an offer we continue to make.”

The United States and its allies suspect Iran is using its nuclear program to produce an atomic weapon – charges Iran denies, saying its aim is to generate electricity. Enriched to a low level, uranium is used to produce nuclear fuel, but further enrichment makes it suitable for a bomb.