China-based AI start-up DeepSeek continues to be the subject of investigations around the world, amid privacy concerns over the data it collects.

Reuters reported that South Korea’s data protection authority said on Thursday that DeepSeek had transferred user information and prompts without permission when the service was still available for download in the country’s app market.

The Personal Information Protection Commission reportedly said in a statement that Hangzhou DeepSeek Artificial Intelligence Co Ltd did not obtain user consent while transferring personal information to a number of companies in China and the United States at the time of its South Korean launch in January.

South Korea

It comes after South Korea’s data agency in February had temporarily suspended DeepSeek from the country’s app stores, with regulators citing privacy concerns.

DeepSeek is based in Hangzhou, in eastern China, which is also the headquarters of tech giant Alibaba.

The South Korean regulator indicated that DeepSeek had acknowledged failing to take into account some of the agency’s rules on protecting personal data.

DeepSeek had become hugely popular in South Korea, as in many other countries around the world, in late January after launching open-source AI models that perform on par with US rivals, but which it said were developed for a fraction of the cost.

According to the Reuters report, South Korea’s data protection agency said on Thursday that DeepSeek had also sent content in AI prompts entered by users to Beijing Volcano Engine Technology Co. Ltd. along with device, network and app information.

DeepSeek reportedly later told the regulator that the decision to send information to Volcano Engine was to improve user experience and that it had blocked the transfer of AI prompt content from 10 April.

Security, privacy

Privacy and security concerns have dogged the DeepSeek since its arrival in January 2025.

In February, Feroot Security, an Ontario-based cybersecurity firm said it had uncovered “concerning code” within the DeepSeek platform that enables direct data transmission from DeepSeek to China Mobile servers.

China Mobile is the world’s biggest mobile operator (by number of users), but was banned from operating in the US market by the FCC in 2019 due to concerns that “unauthorised access to customer…data could create irreparable damage to US national security.”

In 2021 China Mobile was also kicked-off and delisted from the New York Stock Exchange, as were two smaller Chinese state-run telecom providers (China Telecom and China Unicom).

DeepSeek has already been banned on government devices in a number of countries over national security concerns, including South Korea, Italy, Taiwan, Australia, India and the United States.

The US state of Texas banned DeepSeek from government-issued devices, as have the US states of New York, Virginia, Iowa, South Dakota, Nebraska, Tennessee and Arkansas.

And a host of other countries are said to be also probing the national security angle of DeepSeek, including, the UK, Belgium, France, Ireland and the Netherlands.

AI optimisation

However DeepSeek in March had released a series of open-source projects on GitHub, as it revealed details about how it trained its low-cost, high-performance models.

The eight new open-source projects the start-up released were the first time it had disclosed details of the techniques it used to gain optimal performance from compute, communications and storage, three key aspects of model training.

The company’s developers, who are mostly young university graduates, said they were disclosing the company’s “battle-tested building blocks” to share “our small-but-sincere progress with full transparency”.