China has agreed to serious negotiations with Western powers about imposing new sanctions on Iran and President Hu Jintao will attend a multi-nation summit on nuclear security in Washington this month, officials said.

The two moves should dilute tensions between Beijing and Washington after months of quarrels over the yuan currency, Internet censorship, Tibet and US weapons sales to Taiwan, Reuters reports.

The agreement to discuss sanctions marked a significant shift by China after months of fending off Western nations' demands for concerted pressure on Tehran, which they accuse of seeking the means to assemble nuclear weapons.

Beijing has also been coy up to now about whether Hu will attend the April 12-13 nuclear summit in Washington, which would come days before the US Treasury is slated to release a report that could accuse China of manipulating its currency to give its exporters a competitive advantage.

Chinese Foreign Ministry spokesman, Qin Gang, told a news conference on Thursday that Hu would attend the Washington meeting.

The United States' ambassador to the United Nations, Susan Rice, said on Wednesday in New York that her government, Britain, France, Russia and Germany had agreed with China to begin discussing a proposed UN Security Council resolution with new sanctions on Iran.

'This is progress, but the negotiations have yet to begin in earnest,' Rice said in an interview on CNN.

Foreign Ministry spokesman Qin would not discuss specifics of a resolution and stressed China's continued hopes for diplomatic compromise over Iran.

'China is highly concerned about the current situation and will strengthen cooperation with all parties,' he said.

China has long been reluctant to back new sanctions on Iran, a big supplier of oil for the growing Asian power.

Underscoring Beijing's centrality in the accelerating negotiations, Iran's chief nuclear negotiator Saeed Jalili arrived there on Thursday.

Jalili would meet Chinese Foreign Minister Yang Jiechi and Dai Bingguo, a senior Chinese diplomat who serves as a State Councillor advising leaders on foreign policy, said Qin.

'Sanctions now appear to be a foregone conclusion. The likelihood of the resolution passing in the Security Council is high,' said Jin Liangxiang, a Middle East specialist at the Shanghai Institute for International Studies.

As one of the five permanent members of the Security Council, China has the power to veto any resolution. But Beijing appears to be losing some patience with Iran.

Jin said the sanctions were likely to 'hit decision-makers and interests in Iran,' but not seriously affect China's economies and energy ties.

President Barack Obama said on Tuesday that he wanted a new Iran sanctions resolution adopted within weeks.

Iran's Foreign Ministry spokesman, Ramin Mehmanparast, said in Tehran on Thursday that past sanctions against his country had not worked, the official IRNA news agency reported.

He said other nations should not use 'incorrect methods like pressuring and sanctioning.'

Guo Xiangang, a former Chinese diplomat to Tehran, said Beijing was likely to bow only so far to the Western demands for tough sanctions.

'I'd guess that China can accept something a bit harsher (than past sanctions on Iran), but not too harsh. It will remain principally a symbolic warning to Iran,' said Guo, who is now a vice president of the China Institute of International Studies, a government thinktank in Beijing.

He said Beijing would seek to ensure that any financial sanctions did not threaten to entangle its energy and investment deals with Iran.