Chinese foreign vice-minister Ma Zhaoxu is expected to head to the United States next week on a trip likely to lay the groundwork for President Xi Jinping’s visit to Washington later this year, the South China Morning Post has learned. Sources familiar with the matter said Ma, who has played a prominent role in overseeing US-China relations, would be in Washington next week. According to the sources, a stop in Miami – host city of the Group of 20 (G20) summit in December – was also likely to be...