The surveillance tools are identical to those used in Sky Net in China, the largest video surveillance system on Earth, Chinese government research institutes and a company involved in the project said.

At a time when China and the United States are locked in a rivalry on several fronts including trade and technology, Hikvision – which is the world’s largest surveillance technology company and based in Hangzhou in eastern China – has supplied the equipment and software used by an American force that polices a population of about 8.6 million people.

It has been claimed that Hikvision’s system can accurately identify faces regardless of race, whereas some Western-developed technology had previously been more accurate for white people than for black citizens – although the NYPD has not discussed its reasons for using the Chinese technology.

The Sky Net programme, now renamed Pingan Chengshi, or Safe Cities, claimed to have connected 170 million cameras across China last year. By 2020, another 400 million units will be installed, it said, casting a watchful eye on every two citizens. Beijing plans to be able to identify anyone, anytime, anywhere in China within three seconds.