Iranian President Mahmoud Ahmadinejad's announcement that the country has succeeded at creating higher levels of uranium enrichment shows its nuclear intentions are "anything but peaceful," the U.S. State Department said Thursday.

Ahmadinejad said scientists had succeeded at producing a batch of uranium enrichment at a much higher level that it had previously accomplished. The amount was sufficient for running in nuclear power reactors, but still well below the levels needed for weapons grade uranium.

But Iran's nuclear ambitions continue to draw concerns from the United States and European allies who fear Iran is seeking the capability to build nuclear weapons. Iran has rebuffed diplomatic overtures to resolve the issue and is in defiance of UN Security Council demands that it suspend uranium enrichment.

"Should Iran continue down the wrongful course that it's on there will be consequences," State Department spokesman Philip J. Crowley said.

Crowley also said he was skeptical as to the accuracy of Iran's claims of nuclear enrichment capabilities.

"I'm not a scientists but I think there are questions about what Iran's true capability is," Crowley said, adding that Iran has "been boasting number of things for a couple of years, but we are taking their words seriously. It seems as a violation of the UN Security Council resolution."

"It appears that they've attempted a nearly total information blockade - it's an unprecedented attempt to intimidate their own people and it's clear they fear their own people," Crowley said.

"I think we have strong indications that Iran has tried to restrict access to the Internet, and it's not about what the outsiders are doing, but about the fundamental relationship between Iranian government and their people. Iranian people are continuing to protest for their rights.

This continuing intimidation by the Iranian government is a great concern to us, and it shows the increasing bankruptcy of the Iranian regime.

White House Spokesman Robert Gibbs also referred to Iran's claims of its nuclear capabilities, saying the Iranian president Ahmadinejad had said "many things, and many of them turn out to be untrue."

"We do not believe they have the capability to enrich which they claim they have," Gibbs added, saying the actions of Iran have led to the world to be more unified" by defying international obligations.

The comments by U.S. officials came after earlier Thursday British Prime Minister Gordon Brown said the international community was moving closer to imposing sanctions on Iran because of its nuclear program.

Iranian President Mahmoud Ahmadinejad announced on Thursday that Iran was capable of enriching uranium to more than 80 percent purity, coming close to levels experts say would be needed for a nuclear bomb, although he said that was not the country's intention.

"I believe the mood around the world is now increasingly one where, patience not being inexhaustible, people are turning to look at the specific sanctions we can plan on Iran," Brown told BBC.

Officials: UN set to pass tighter Iran sanctions

Senior United Nations officials told Haaretz that a Security Council resolution tightening the sanctions on Iran has become more likely, and that the resolution is probably going to be approved.

Observers in both New York and Washington estimate that China will think twice about using its veto on a resolution after Russia recently threw its support behind a move against Iran. A veto could expose Beijing as isolated and out of touch with its fellow Security Council members.

China could also abstain from voting and allow the decision to be made by a simple majority. However, the sources told Haaretz, the United States is still trying to obtain Chinese support for the sanctions.

Ahead of its push for international sanctions at the UN, the U.S. sought on Wednesday to ratchet up pressure on Iran by imposing its own sanctions on elements of Iran's Revolutionary Guard Corps, which Western intelligence officials believe is spearheading Iran's nuclear program.

The Treasury Department said it was freezing the assets in U.S. jurisdictions of Revolutionary Guard Gen. Rostam Qasemi and four subsidiaries of a previously penalized construction firm he runs because of their alleged involvement in producing and spreading weapons of mass destruction.

U.S. officials said the measures were intended as a model for wider action at the UN.

"The United States is seeking to reach a consensus between the five permanent members of the UN Security Council on the sanctions issue," one of the sources said. "This would allow it to present the five superpowers as a united coalition, which would increase the impact of the sanctions."

According to estimates in Washington and New York, a first American draft for the new resolution will be circulated among Security Council members in early March at the latest, and the vote will take place at the end of the month.

"To be honest, nobody knows for certain at the moment what China is going to do," a senior official in New York told Haaretz. "But at the end of the day, China is sensitive about its position as a superpower, and will not be able to ignore the position of other superpowers, including Russia, who support tightening the sanctions. It's not going to go against them by undermining the resolution."

The New York Times on Wednesday quoted officials in the Obama administration who said the U.S. president has been applying the same persuasion tack with China he earlier successfully used with Russian president Medvedev. According to the daily, Obama has placed sanctions on Iran at the top of his priorities in recent contacts with Beijing.

Experts, however, warned that the same tactics that brought success with Russia may not work with China. A scheduled White House visit by the Dalai Lama has infuriated the Chinese, as did a recent arms deal between the United States and Taiwan.

The Americans had earlier planned to begin promoting the resolution in February. France, which supports a tough line on Iran, is this month's president of the Security Council.

""This is a critical time for Iran's relationship with the rest of the world."

Brown said the international community did not want to impose sanctions but would do so if Iran did not cooperate more fully over its nuclear plans.