China and the United States are ahead of the global competition to dominate artificial intelligence (AI), according to a study by the United Nations World Intellectual Property Organization (WIPO) published on Thursday.

The research found tech giant IBM had by far the biggest AI patent portfolio with 8,920 patents, ahead of Microsoft with 5,930, and a group of mainly Japanese tech conglomerates.

China accounted for 17 of the top 20 academic institutions involved in patenting AI and was particularly strong in the fast-growing area of "deep learning" - a machine-learning technique that includes speech recognition systems.

"The US and China obviously have stolen a lead. They're out in front in this area in terms of numbers of applications and in scientific publications," WIPO Director-General Francis Gurry told a news conference.

US President Donald Trump has accused China of stealing American innovations and technology and has slapped trade tariffs on $234bn of Chinese goods to punish Beijing.

China said in December it resolutely opposed "slanderous" accusations from the US and other allies criticising China for economic espionage and stealing intellectual property and company secrets.

Gurry acknowledged there were accusations about China's behaviour.

However, he said there was no doubt it had embraced the global intellectual property system, with the world's largest patent office and the largest number of domestic patent applications.

"They are serious players in the field of intellectual property," he said.

Creeping intelligence

According to the study, AI-linked patent filings make up just 0.6 percent of the global patent pool, but that number is expected to swell with widespread implications.

Patent applications in machine learning, which includes techniques used by ride-sharing services to minimise detours, averaged annual growth of 28 percent between 2013 and 2016, the last year for which data is available, because of an 18-month period before confidential applications are publicly disclosed.

Much of that growth came from deep learning, which overtook robotics as it ballooned from 118 patent applications in 2013 to 2,399 in 2016.

The single most popular AI application was computer vision, used in self-driving cars, and mentioned in 49 percent of all AI-related patents.

The WIPO study found companies were far more active than universities and other public research institutions in filing AI-related patents, accounting for 26 out of the 30 top applicants in the field.

The study is based on data from 2016, but Gurry said there was no reason to believe the astronomical surge in such filings had not continued since then.

"The general direction that we see ... is that this is infiltrating most things," Gurry said.

He stressed it was not up to WIPO to make a judgement call on whether the new technologies were good or bad, but the UN agency aimed to provide a wealth of empirical data to inform important and much needed societal discussions around AI and its implications.