The British Army is using a Chinese-owned app that the United States military has ordered its personnel to stay away from over Washington's fears that it could be used for spying.

The British authorities intend to use video-sharing app TikTok as part of their unclassified efforts to recruit young people to join the armed forces.

While the US authorities have launched an investigation into whether Beijing ByteDance Technology Co, the owner of the app popular with teenagers, is sending information about users to the Chinese authorities. Under the username "BritishArmyHQ", the British Army posts short videos of activities such as soldiers answering questions, taking part in training exercises, and firing tanks' guns.

The MailOnline tabloid said the UK military's TikTok accounts have more than 50,000 followers.

TikTok, launched in 2017, is also known as Douyin in China.

Colonel Chris MacGregor said on Twitter that the British Army has been "playing with" TikTok, one of the most downloaded apps in the US last year, in order to "understand it better".

He said the platform is only being used for the "unclassified passage of information".

A British Army spokesman added: "We encourage our personnel to engage with social media and provide guidance on how to use it safely and appropriately, including making sure they protect personal and operational security."

The co-founder and head of TikTok, Alex Zhu, has said in the past that he would not comply with any request from the Chinese authorities to share users' sensitive data.

A TikTok spokesman told Mail-Online: "We take our responsibility to protect our users' data and privacy extremely seriously. As a young company that is growing fast, people naturally have questions about these issues. We are committed to helping people better understand our policies and how TikTok works."

The spokesman added that the company has never been asked to pass on data to the Chinese authorities.

"UK user data is stored securely in the US with back-up redundancy in Singapore," he added.

The Reuters reported last week that the US Army decided to ban the use of TikTok after US Senator Chuck Schumer urged a review of the app's potential risks.

US Army Secretary Ryan McCarthy subsequently said the military authorities had banned its use while they conduct an assessment.

A US Army spokesperson told Reuters the authorities had decided to "err on the side of caution". The US prohibition means military personnel cannot use the app for recruitment, or use it while in uniform or while performing official duties.

In addition, the Committee on Foreign Investment in the US has launched a national security review of ByteDance's $1-billion 2017 purchase of US social media app Musical.ly, which was merged with TikTok in August 2018.