(Reuters) -Social media platform X went down for nearly 12,000 users on Monday, which owner Elon Musk said was the result of a cyberattack.

"There was (still is) a massive cyberattack against X. We get attacked every day, but this was done with a lot of resources. Either a large, coordinated group and/or a country is involved," Musk said in a post on the platform.

A source in the internet infrastructure industry said X had been hit by several waves of denial of service beginning around 9:45 UTC.

The source spoke on the condition of anonymity as the person was not authorized to speak publicly on the matter.

Denial of service works by overwhelming targeted websites with rogue traffic. Such attacks are not necessarily sophisticated but they can cause significant disruption.

X was facing intermittent outages according to Downdetector, restricting 11,745 users in the U.S. from accessing the platform, as of 1.46 pm ET.

The number of outage reports rose to around 26,579 after falling briefly, user-submitted data on the outage-tracking website showed. The number was as high as 40,000 earlier in the day.

(Reporting by Rishi Kant in Bengaluru, Juby Babu in Mexico City and Raphael Satter in Washington; Editing by Maju Samuel, Anil D'Silva and Shounak Dasgupta)