US President Donald Trump's administration on Friday announced it had imposed export controls on China's biggest chipmaker, SMIC, restricting its access to US technology over its alleged ties to the Chinese military.

"We're adding SMIC to the entity list mostly because we need to make sure US intellectual property and manufacturing capabilities are not being used by SMIC's clients to continue to support the military-civil fusions efforts within China," a senior official in the Commerce Department said.

The designation means US companies must apply for a license before exporting to SMIC, and specifically targets the Chinese firm's ability to acquire materials for producing chips of 10 nanometers or smaller, the best class in the industry. 

The Commerce Department official said Washington has evidence SMIC has worked with the Chinese military on developing short- and medium-range ballistic missiles and exoskeletons for soldiers, but had been discussing with SMIC for months on a way to avoid the designation.

"We simply no longer could stand by and watch our adversary using our technologies to support its military capabilities," the official said.

The decision increases pressure on the chipmaker that has received billions of dollars in support from Beijing and is at the heart of its efforts to improve the country's technological self-sufficiency.

Under Trump, the United States has repeatedly targeted its global rival through the entity list, which now includes a few hundred Chinese companies and subsidiaries.

Trump is set to hand power to President-elect Joe Biden on January 20.