Elon Musk says X (formerly Twitter) has been hit by a "massive cyber-attack" on Monday, after thousands of users in the UK and US reported outages.

Mr Musk, who has owned the platform since late 2022, suggested the attack may be ongoing.

"We get attacked every day, but this was done with a lot of resources," he wrote in a post on X.

He suggested that "either a large, coordinated group and/or a country is involved".

The BBC has approached X for comment.

It comes after platform outage monitor Downdetector said it had seen tens of thousands of reports from US users of technical issues affecting the platform on Monday.

There were more than 8,000 outage reports from UK users shortly before 14:00 GMT, following a brief but notable surge of reports on Monday morning.

Many users trying to access the platform and refresh feeds on its app and desktop site during Monday's outages were met with a loading icon.

Alp Toker, director of Netblocks, which monitors the connectivity of web services, said its own metrics suggested the outages could well be linked to a cyber-attack.

"What we've been seeing is consistent with what we've seen in past denial of service attacks, rather than a configuration or coding error in the platform," he told BBC News.

He said the organisation has seen several major outages spanning more than six hours on Monday, "each having global impact".

"This is amongst the longest X/Twitter outages we've tracked in terms of duration, and the pattern is consistent with a denial of service attack targeting X's infrastructure at scale," he added.

A distributed denial of service (DDoS) attack is an attempt to take a website offline by overwhelming it with internet traffic.

Mr Musk has previously claimed that the platform has been targeted by DDoS attacks, but these have not been confirmed.