Dozens of tall, pretty models in heavy make-up stroll around in alluring cheerleader outfits, but Liu Qing has no time to spare for the girls. He criss-crosses a giant convention hall amid hundreds of exhibitors, handing out business cards and chatting to potential customers.

"This is a great opportunity to get to know major video game companies, learn how the industry operates and to do business with them," says Liu, chief executive of a start-up mobile game company. The round-faced 33-year-old, in slacks and slippers, handed out more than 200 business cards at ChinaJoy, the country's largest internet game convention, held in Shanghai late last month.

China announced trade sanctions for six American companies on Thursday, another flare-up in its wide-ranging rivalry with the United States as the two countries prepare for a hotly anticipated meeting between their leaders.

The affected enterprises – unmanned vehicle firm Saronic Technologies, satellite company Aerkomm and subsea engineering firm Oceaneering International – have “engaged in so-called military-technical cooperation with Taiwan, severely undermining China’s national sovereignty, security and development interests” despite strong opposition, the ministry said.