A Chinese official walks by the China and US national flags before a meeting between US Commerce Secretary Gina Raimondo and Chinese Minister of Commerce Wang Wentao at the Ministry of Commerce in Beijing on August 28, 2023. Andy Wong / POOL / AFP / File 

The US government on Thursday added 37 Chinese entities to its trade blacklist, citing national security concerns, with 11 of them accused of being connected with a suspected spy balloon that flew over sensitive areas of the United States last year.

Entities including companies and research institutions on the list are restricted from doing business with US firms and must gain Commerce Department approval before obtaining goods and technologies from them.

Of the 37 entities, the department said 22 were put on the list for their links to China's efforts to improve quantum technology and for acquiring or seeking to acquire US-origin items to boost the country's quantum capabilities.

It said some of them are also associated with advancements in China's nuclear programs or have been involved in the export of controlled items to Russia following its war against Ukraine.

"Today's action is another decisive step in addressing challenges posed by the People's Republic of China and its military modernization," Under Secretary of Commerce for Industry and Security Alan Estevez said in a statement.

He said the United States must remain vigilant in blocking such entities from accessing US technologies that could be used to undermine its national security.

The giant balloon, suspected of carrying out espionage over the United States, was detected in February last year. The incident became a new flashpoint between the United States and China, and led to an abrupt postponement of US Secretary of State Antony Blinken's planned visit to Beijing.

US forces later shot down the balloon, which was the size of about three buses, off the coast of South Carolina, infuriating China.

Beijing insisted it was a civilian craft being used for weather research and was accidentally blown off course by strong winds.

Months after the incident, tensions between the two countries gradually eased as senior officials reopened lines of communications. US President Joe Biden and Chinese President Xi Jinping also met in person in November last year near San Francisco and agreed to manage differences.

Nonetheless, the Biden administration continues to view China as the most significant geopolitical threat, with tensions simmering between Washington and Beijing on a number of issues.