TAIPEI, Taiwan (AP) -- China imposed export controls Wednesday on eight companies tied to Taiwan's military as the self-ruled island started annual military exercises.

China's Commerce Ministry added eight Taiwan-based firms including aerospace and shipbuilding companies, to an export control list, citing national and regional security concerns.

The banned companies include defense supplier Aerospace Industrial Development Corporation (AIDC), drone maker Jingwei Aerospace Technology Co., and CSBC Corporation, Taiwan's largest shipbuilding company.

The new rules, effective immediately, prohibit the export to the listed enterprises of "dual-use items," a term referring to goods that can be used for both civilian and military purposes.

The ban comes just as Taiwan begins its annual Han Kuang military drills, which will simulate defenses against a possible invasion by China. This year's drills are set to be the largest and longest ever, lasting about 10 days, twice as long as last year's exercises.

China regards self-ruled Taiwan as its own territory, to be annexed by force if necessary. Beijing has branded Taiwanese President Lai Ching-te as a separatist and refuses to speak to him.

The United States, like most countries, doesn't recognize Taiwan as a country, but is bound by its own laws to provide it with the means to defend itself.