Leaders of 20 major economies on Friday refused to back a U.S. push to make China boost its currency's value, keeping alive a dispute that raises fears of a global trade war amid criticism that cheap Chinese exports are costing American jobs.

A joint statement issued by the leaders including President Barack Obama and China's Hu Jintao tried to recreate the unity that was evident when the Group of 20 rich and developing nations held its first summit two years ago during the global financial meltdown.