The limits to Washington's bridge-building effort with the European Union were laid bare yesterday when a US official pushed the EU to change policy on China, played down prospects for EU success in talks with Tehran and highlighted internal EU divisions on Russia.

On the last day of a European tour, Robert Zoellick, US deputy secretary of state, tried to build on the message of co-operation expressed by President George W. Bush during his visit six weeks ago. But he stepped up criticism of the EU's plans to lift its arms embargo on China even though the move now seems likely to be delayed.