Deputy Secretary of State Robert Zoellick, the architect of US-China policy and Washington's pointman on Sudan, resigned to take up a position with Wall Street giant Goldman Sachs.

US Secretary of State Condoleezza Rice(L) announces the resignation of Deputy Secretary of State Robert Zoellick(R) at the US State Department in Washington, DC. Zoellick, a leading architect of US-China policy and Washington's pointman on Sudan, said he was returning to private investment giant Goldman Sachs. [AFP]

"It is time for me to step down," Zoellick told a news conference at the State Department, with Secretary of State Condoleezza Rice by his side.

Rice said, "Today, it is not without considerable sadness that I announce that Bob Zoellick will be leaving the department in coming weeks."

There was no indication of who will succeed Zoellick.

The 52-year-old former US trade representative was reported to have held talks with Wall Street banks after not getting the treasury secretary's post in a recent shuffle.

President George W. Bush last month nominated Henry Paulson in place of John Snow.

Zoellick, a Harvard-trained lawyer, was a senior international advisor to Goldman Sachs in the 1990s.

"Deputy Secretary Zoellick has been one of Secretary Rice's closest and most valued advisors on every single international issue and she will reluctantly accept his resignation," a Rice advisor said.

A US official, speaking on condition of anonymity, said Zoellick believes it is a good time to move now because he feels he has accomplished goals that he had made at the State Department.

Zoellick was confirmed in the post by Congress in February last year and has been helping Rice recruit her team at the department, which she took over 18 months ago.

He took charge of negotiations with China and led strategic dialogue with the Beijing government aiming to make China "a responsible stakeholder" in world affairs.

Zoellick also tried to nail down an accord with the Sudanese government over the strife in the Darfur region.

As the US trade representative, Zoellick completed negotiations to bring China into the World Trade Organisation and played a central role in the launch of the Doha round of global trade talks in 2004.

He also completed free trade agreements with Singapore, Chile, Australia, Morocco, five Central American states and Bahrain.