The Associated Press says it obtained an intelligence report from a nation that belongs to the International Atomic Energy Agency (IAEA) and that it was given to the wire service on condition of anonymity.
It says a two-page summary of the document says the uranium deal with "elements" inside Kazakhstan could be completed within weeks and that Tehran is willing to pay $450 million for the shipment.
The wire service quotes the report as saying, "The price is high because of the secret nature of the deal and due to Iran's commitment to keep secret the elements supplying the material." An official of the country that drew up the report said "elements" referred to state employees acting on their own without approval of the Kazakh government.
Iran's mission to the United Nations rejects the report as baseless and "a fabrication."
A Kazakh Foreign Ministry spokesman, Yerzhan Ashikbaev, said earlier that his country's uranium activities were in compliance with IAEA demands.
Ian Kelly, a spokesman for the U.S. State Department, said the transfer of any purified uranium ore -- known as "yellowcake" -- to Iran would constitute a "clear violation of UN Security Council sanctions." Yellowcake can be enriched for use as nuclear fuel or nuclear weapons.
Meanwhile, Iran has repeated its rejection of the international community's end-of-the-year-deadline to accept a uranium enrichment deal, setting the stage for a new round of sanctions already under discussion by the United States and its allies.
The United States and the four other permanent members of the United Nations Security Council -- Britain, China, France, and Russia -- as well as Germany, have given Iran until January 1 to accept a plan brokered earlier by the International Atomic Energy Agency (IAEA) to export the bulk of its low-enriched uranium abroad for processing into fuel for its Tehran research reactor.
The deal is intended to alleviate Western concerns over Iran's suspected nuclear-weapons program by limiting the country's ability to highly enrich the uranium on its own for possible weapons use. Iran denies it is pursuing nuclear weapons, and stands by its right to pursue nuclear technology for civilian purposes.
While initially expressing agreement to the deal, Iran proposed changes that the international community and IAEA have rejected, including handing over only parts of its stockpile of low-enriched uranium in exchange for processed uranium. Tehran also suggested that it might purchase processed uranium for civilian use from abroad. The Iranian position was seen by many observers as a rejection of the IAEA deal.
Now, Foreign Minister Manuchehr Mottaki says Iran "can no longer wait" for an answer to its counteroffer.
As many as 10 people are reported to have been killed in clashes with state security forces and many more have been arrested.
On December 28, U.S. President Barack Obama took time away from his holiday in Hawaii to urge the Iranian government to release the protesters it has detained and to "abide by the international obligations that it has to respect the rights of its own people."
"What's taking place within Iran is not about the United States or any other country - it's about the Iranian people and their aspirations for justice and a better life for themselves," he said. "And the decision of Iran's leaders to govern through fear and tyranny will not succeed in making those aspirations go away."
The tense human rights situation in Iran has complicated the sanctions debate. Punitive measures inevitably impact civilians, which Washington is keen to avoid in the midst of the nationwide unrest.
The head of Obama's National Security Council, Denis McDonough, says the White House is gauging the views of U.S. friends and allies about "the next step in the process," and said both unilateral and United Nations sanctions are being considered.
Some analysts point to what they see as a "course correction" in the White House's thinking.
U.S. Seeks Narrow Sanctions
Earlier this month, the U.S. House of Representatives passed a bill that would punish companies that sell refined petroleum products to Iran, which imports 40 percent of its gasoline. The measure is expected to easily pass in the Senate in January.
But a senior State Department official told "The Los Angeles Times" that the White House favors more targeted sanctions.
The official, who declined to be identified because he was not authorized to comment, said the goal is now to make any new sanctions "as narrow as they can be." He characterized Congress' desire to cut off gasoline supplies as too sweeping and therefore "tough to do."
He also acknowledged that the West's uranium enrichment offer is "off the table."
In an interview with RFE/RL's Radio Farda, U.S. Senator Joseph Lieberman (Independent, Connecticut) said he is one of the key supporters of bringing the petroleum sanctions bill to a vote when the Senate reconvenes.
He called the move a response both to Tehran's failure to end its controversial nuclear program and its continuing abuse of human rights.
"The economic sanctions legislation that the U.S. will consider in January will not simply be a reaction to the failure of the Iranian government to negotiate in good faith on the nuclear program," he said. "It will also be a specific empowerment to [President Barack Obama] and [Secretary of State Hillary Clinton] to take action against the current Iranian leadership because of its human rights abuses."
Lieberman added, "It's clear that the president has lost patience, and will now work very hard for economic sanctions against the regime and against the leaders of the regime in Tehran, and hopefully there will be support" from members of the Security Council, and Germany, the group known as the P5+1.
Despite vigorous diplomatic efforts by the United States to convince traditional Iran allies China and Russia to support tougher sanctions, their 'yes' votes in the UN Security Council are considered a long shot.
Lieberman said that won't prevent the United States from acting.
"It appears that China and Russia are moving toward being more supportive than they have traditionally been. But, frankly, if China and Russia are not supportive, the United States will go ahead with our European allies -- I am confident -- to impose such sanctions," Lieberman said.
He added, "I regret it, but it is what the government in Tehran has brought on itself by its failure to engage and to respond to President Obama's initiatives."
Radio Farda's Hossein Aryan contributed to this report; with agency reports
Radio Free Europe/Radio Liberty