World leaders’ resolve at the Group of Eight summit in St Petersburg to unblock the troubled Doha round of trade talks will be tested when trade ministers meet in Geneva on Sunday, Susan Schwab, US trade representative, said on Tuesday.

“We should see the impact of the G8 leaders’ commitment by this weekend,” she said in Geneva, before flying back to Washington for meetings with key Congressional leaders to discuss the US negotiating position. “The sense of resolve could translate into the breakthrough we have been looking for for months.”