Elon Musk has been warned he must protect Twitter users from harmful content after he struck a $44bn deal to buy the social media giant.

Axar.az reports that the billionaire vowed to relax content restrictions, sparking fears from human rights groups it could lead to a rise in bullying and misinformation.

"Regardless of ownership, all social media platforms must be responsible," Boris Johnson's spokesman said.

The European Commission also warned Mr Musk that he must protect users.

"Be it cars or social media, any company operating in Europe needs to comply with our rules - regardless of their shareholding," Thierry Breton, commissioner for the internal market at the EU executive, warned in a tweet.

The European Union has said its new online rules will "overhaul" the digital market, including how tech giants operate.

Once they come into force, there will need to be greater transparency around why content is recommended to users, or why they are being targeted with certain ads, for example.