The United States is pressing for very tough new sanctions against Iran this month, a top US aide said Sunday, suggesting that the move could help bring about "regime change."

"We're... going through the UN this month to present sanctions," President Barack Obama's national security advisor, retired general James Jones, told Fox News Sunday.

While the US is not actively seeking to destabilize Iran, which has been rocked by months of anti-government protests since disputed elections last year, Jones said additional sanctions could nevertheless have that effect.

"We know that internally there is a very serious problem. We're about to add to that regime's difficulties by engineering, participating in very tough sanctions, which we support," he said.

"Not mild sanctions. These are very tough sanctions. A combination of those things could well trigger a regime change -- it's possible."

Jones said that "the combination of internal and external problems are certainly not going to make life easier for the government of Iran."

His remarks cane with Secretary of State Hillary Clinton in the Middle East to build the US case for tougher sanctions over Iran's suspect nuclear activities in meetings with key Arab and Muslim leaders.

Jones said there was already "tremendous support" for new sanctions against Iran, but admitted: "We need to work on China a little bit more.

"Russia is supportive and is on board, and has been a steady friend and ally on this with president Obama," he said, warning: "I think Iran needs to weigh very carefully how it wishes to proceed."

With Russia having hardened its stance, China is the sole veto-wielding hold-out to further sanctions at the UN Security Council and is still pushing for further negotiations

However US Vice President Joe Biden expressed confidence Sunday that the Chinese would ultimately join the other nations in backing measures to punish Iran.

"I believe we'll get the support of China to continue to impose sanctions on Iran to isolate them, to make it clear that in fact they cannot move forward," he told NBC's "Meet the Press" program.

There is strong backing for sanctions from Britain and France -- the remaining veto-wielding members -- as well as from Germany, which has also been involved in months of negotiations to try and get Iran to change tack.

The West is trying to convince Tehran to sign on to an UN-brokered deal that calls for it to ship its stockpile of low-enriched uranium (LEU) abroad for further processing.

So far, Iran has defied three sets of UN Security Council sanctions, insisting its nuclear drive is peaceful.

This week it boasted that it had begun enriching its uranium stockpile to the 20 percent level that would allow it to fuel its research reactor.

Western powers believe Iran's eventual goal is to make the highly enriched uranium that would allow it to build a nuclear weapon and radically alter the balance of power in the already unstable Middle East and Central Asia.

But analysts warn that President Mahmoud Ahmadinejad may be exaggerating Iran's ability to advance its nuclear program in order to force the West to negotiate on his terms and reinforce his shaky position at home.

Biden supported that view, asserting Sunday that Iran "is not a nuclear power."

"The progress that Iran has made on the nuclear front is greatly exaggerated in my view," Biden told NBC, saying that Iran made the announcement to draw attention away from ant-government protests and other domestic problems.

"I can understand why Ahmadinejad would make that assertion, to divert the world's attention from the abuse of the civil liberties and civil rights of the people of Iran," Biden said.

Thirty-one years after the Islamic revolution, Tehran's authoritarian regime is facing unprecedented street protests from a large but diffuse opposition movement, which some think could topple the government.

Clinton asks Gulf to pressure Iran, sees changes in China
Doha (AFP) Feb 14, 2010 - US Secretary of State Hillary Clinton on Sunday urged Muslim leaders to help halt Iran's sensitive nuclear work and detected a possible shift in China toward supporting sanctions against Tehran.

At the start of a three-day Gulf visit, Clinton told Iran's neighbours it appeared increasingly evident Tehran is seeking nuclear weapons and warned the Revolutionary Guards' rising power poses "a direct threat" to all.

Frustrated that a year-long drive to engage Iran in nuclear and other talks has yielded little, President Barack Obama's administration last week imposed fresh unilateral sanctions against the Islamic Revolutionary Guard Corps.

US officials also want the UN Security Council to draft new sanctions against a force they say runs Iran's nuclear programme, supports anti-US and anti-Israeli militants and cracks down on Iranian anti-government protesters.

"It's time for Iran to be held to account for its activities which do already and can continue to have destabilising effects," she said in a speech to the US-Islamic World Forum, set up after the September 11, 2001 attacks.

"I would like to figure out a way to handle it," Clinton said after voicing fears about "the rise of the influence and power" of the Revolutionary Guards. "Certainly, we don't want to be engaging while they're building their bomb."

During a regional tour that will also take her to Saudi Arabia, the chief US diplomat added to the US sense of urgency after Iran began Tuesday to enrich uranium to 20 percent purity while insisting its intent was peaceful.

"Iran leaves the international community little choice but to impose greater costs for its provocative steps," she said after talks with Qatar's emir Sheikh Hamad bin Khalifa Al-Thani, and Sheikh Hamad bin Jassim Al-Thani, who is both foreign minister and prime minister

"We are now working actively with our regional and international partners... to prepare and implement new measures to convince Iran to change its course," she said.

Obama's National Security Adviser James Jones said earlier in Washington that the United States is pressing for "very tough" new sanctions against Iran this month, suggesting the move could help bring about "regime change."

Clinton also met in Doha with Turkish Prime Minister Recep Tayyip Erdogan whose country has good ties with Iran and has repeatedly offered to serve as mediator on the nuclear issue.

Turkey's foreign minister is due to visit Iran in the coming week.

Clinton struck an upbeat note about support for sanctions among the five veto-wielding members of the Security Council -- the United States, Russia, China, Britain and France.

She said Russia has said "publicly and privately that it can and will support sanctions," and detected a shift in the Chinese position.

"The weight is maybe beginning to move toward not wanting to be either isolated or inadvertently contributing to instability that would undermine their economic interests," she said.

She recalled China's investment stake in Iran and its oil imports from that country.

On the plane from Washington to Doha, Clinton's Middle East aide Jeffrey Feltman said Washington would ask for oil-rich Saudi Arabia's help in pressing China to join the US drive for sanctions against Iran.

But Feltman neither confirmed nor denied suggestions the administration would ask the Saudis to offer China supply guarantees in return for winning Beijing's support for new UN sanctions.

Clinton is due to meet Saudi Arabia's King Abdullah and Prince Saud al-Faisal, the foreign minister, in Riyadh on Monday.

In a follow-up to a speech Obama gave in Egypt last October in which he called for a "new beginning" with the world's Muslims, Clinton shared US disappointment with the region about the failure to achieve a breakthrough in the Arab-Israeli peace process.

"But we need to remember that neither the United States nor any country can force a solution. The parties must resolve their differences through negotiations," she added.

"We are committed to our role in ensuring that negotiations begin and succeed," she said.

The Arab and Muslim enthusiasm that greeted Obama's victory in the US election in 2008 has given way to frustration and disenchantment, particularly over the deadlock in the peace process.

On another issue sensitive to Muslims, Clinton said her country has no interest in either "occupying" Afghanistan or abandoning the war-torn country.