China threatened to impose sanctions on US arms firms and cut cooperation with Washington unless it cancels a $6.4bn arms sale to Taiwan, in an unprecedented move signalling Beijing's growing global power.
Although Beijing ritually protests US weapons sales to the island, it has not previously targeted the companies involved in the trade. Although the US restricts arms sales to China, a number of the companies that would supply systems involved in the new Taiwan package, which include Boeing, United Technologies, Lockheed Martin and Raytheon, could face pressure in other business areas.
Boeing, in particular, has been counting on China sales of commercial aircraft in its battle with Airbus. Boeing, which warned on Friday that it expects revenue to fall this year, declined to comment on the Chinese threat. Beijing centrally manages aircraft purchasing and political factors have played a role in the past.