"We must now realise the promise of America by trusting God, unifying our vision and building our future. I am running for president of the United States," he wrote.
He's appeared on Oklahoma's presidential ballot after paying the $35,000 filing fee earlier this week, but questions remain over whether he's actually running.
His Mount Rushmore tweet gathered over 79,000 likes.
It comes after a member of his campaign team, Steve Kramer, confirmed to New York Magazine's Intelligencer that Kanye was "out" of the 2020 presidential race.
Kramer didn't say why West had allegedly withdrawn.
But about an hour after Kramer's statement, West shared a video of himself registering to vote in Wyoming.
In the video, he says to his fans: "I want to show you how I just registered to vote", alongside the caption: "I thank God and I am so humbled at the opportunity to serve".
And the results of a new US presidential poll released on Tuesday revealed West had the support of just 2 per cent of voters.
