The World Trade Organization's long-running Doha round is stuck and a deal is impossible until China and other big emerging countries join real negotiations to open their markets, a top US trade official said on Thursday.

Michael Punke, US ambassador to the WTO, said China was stalling on talks on the global trade round sought by the United States, but there were hopeful signs that Brazil and India were willing to negotiate.

"When it comes to China however we're getting no engagement whatsoever, not even in terms of process," he told Reuters. - Reuters