Washington: President Barack Obama says the United States will continue to "ratchet up the pressure" on Iran to reveal its nuclear intentions to the rest of the world.

In an interview broadcast Friday on CBS`s "The Early Show," Obama said "all the evidence" indicates that Tehran is trying to get a nuclear weapons capacity. With such a capability, Obama said that Iran could "destabilize" life in the Mideast and trigger an arms race in the region.

Obama said, "I think the idea here is to keep on turning up the pressure." He had said earlier this week he wanted new, stronger UN sanctions to be in place by late spring. The president also said he believes the country has become "further isolated" from the rest of the world since he took office.

Earlier, US President Barack Obama urged Chinese President Hu Jintao to work together on the Iranian nuclear standoff, the White House said, as Hu appealed for "healthy and stable" relations between the two nations.

Obama also welcomed Hu`s attendance at the international summit on nuclear security to be held in the US capital later this month, saying it would be an "important opportunity for them to address their shared interest in stopping nuclear proliferation and protecting against nuclear terrorism”.

Earlier on Thursday, the White House said it was pleased China agreed to join talks at the United Nations on toughening sanctions on Iran.

White House spokesman Bill Burton said the move proved that despite lingering "disagreements we can work together on issues like nuclear proliferation”.

The rare hour-long telephone conversation late Thursday between the leaders came as the powers seek to overcome deep strains in their ties on multiple fronts, included the valuation of Chinese currency, US arms sales to Taiwan and two countries` relationship over Tibet.

The pair discussed the importance of a "positive bilateral relationship”, the White House said in statement following the phone call from Air Force One.

Hu told Obama that both sides should "respect each other`s core interests and major concerns and properly handle differences and sensitive issues," the Chinese Foreign Ministry said in a statement.

He also called on the two nations to make "unremitting efforts towards cooperative, positive and comprehensive" ties, Bejiing said.

China has previously opposed the imposition of tough new UN sanctions on the Islamic republic, and said on Thursday it was working for a "peaceful resolution" of the Iranian nuclear standoff.

Iran, which sent its top nuclear negotiator to Beijing, described the talk of new international action as an empty threat.

The presence of Tehran`s chief nuclear negotiator Saeed Jalili on a visit to Beijing meanwhile highlighted China`s role in the tense UN Security Council debate on Iran`s uranium enrichment.

The United States and its allies suspect the programme is part of a drive to develop a nuclear bomb, while Tehran insist its activities are geared toward a civilian energy program.

Obama said on Tuesday he wants a fourth round of UN sanctions agreed upon within weeks.

China, which has a close diplomatic and trade relationship with Iran, and is one of five veto-wielding members of the Security Council, has repeatedly called for a negotiated settlement rather than new punitive action.

Hu`s announced appearance at the nuclear security summit in Washington on April 12-13 and the lengthy conversation between him and Obama Thursday appeared to mark a slight easing of tensions after months of frayed relations between Washington and the rising Asian giant.

Chief among bilateral irritants is currency, with some 130 US lawmakers calling on Treasury Secretary Timothy Geithner to accuse China of manipulation of its yuan`s value for trade advantage -- and threatening legislation if he does not.

Tensions have risen on a number of other fronts, including the arms sales to Taiwan and Beijing`s angry protests earlier this year over Obama`s meeting with Tibet`s exiled spiritual leader the Dalai Lama.

Other disputes include human rights, climate change and Internet freedom after Google reported cyberattacks by China.

US Secretary of State Hillary Clinton was earlier this week upbeat over the possibility of slapping new sanctions on Tehran, saying the P5+1 group -- permanent council members Britain, China, France, Russia and the United States, plus Germany -- "continues to be unified”.

"There will be a great deal of further consultation, not only among the P5+1, but with other members of the Security Council and other nations" in the coming weeks, Hillary said.

Bureau Report