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.

“China has always handled the list with prudence, targeting a small number of foreign entities that endanger our national security in accordance with the law. Honest and law-abiding foreign entities have no cause for concern.”

Three other American firms – shipbuilder Huntington Ingalls Industries, engineering and construction manager Planate and services provider Global Dimensions – were added to the export control list, preventing them from receiving shipments of items from China determined to have military and civilian applications.