Speaking at a rally at a Washington DC arena, the billionaire pounded his chest and aggressively shot his arm out in a stiff-armed salute.

He then turned around and did it again to another part of the cheering crowd.

“Some elections are important, some are not. But this one, this one really mattered and I just want to say thank you for making it happen,” he said before the gesture.

“It is thanks to you that the future of civilisation is assured.”

When Musk posted a video of his speech online the clip cut away to shots of the audience at the moment of the gesture.

The South African-born billionaire has posted repeatedly on X since his speech, but has not addressed the gesture.

As you might expect, comments online were quick to speculate about the nature of the gesture.

Some online commenters likened the gesture to a Roman salute, which is also known as a fascist-style salute.

“In this moment, all sides should give one another a bit of grace, perhaps even the benefit of the doubt, and take a breath. This is a new beginning. Let’s hope for healing and work toward unity in the months and years ahead.”

Musk has been appointed to head a new cost-cutting body in the Trump Administration, named the Department of Government Efficiency (DOGE).

He was named the co-leader of the department alongside Trump acolyte and former presidential candidate Vivek Ramaswamy.

But even as the inauguration celebrations went on, it was reported Ramaswamy would leave DOGE.