US Deputy Secretary of State Robert Zoellick, a leading architect of Washington's China policy, announced his resignation Monday and said he was returning to private investment bank Goldman Sachs. Zoellick, 52, a former US trade representative and Harvard-trained lawyer, was a senior international adviser with the firm in the 1990s. His resignation follows the appointment of Goldman Sachs executive Henry Paulson to replace departing treasury secretary John Snow, a job Zoellick reportedly had wanted. As the US trade representative, Mr Zoellick completed negotiations to bring Beijing and Taipei into the World Trade Organisation and played a central role in the launch of the Doha round of global trade talks in 2004. He did not give reasons for his departure but officials said he was expected to leave the White House next month.