Trump is spending the weekend at his properties in Florida.
"Will be having many meetings this weekend at The Southern White House," he wrote in a tweet on Saturday morning.
The president spent the morning at the Trump International Golf Club before returning to his Mar-a-Lago resort. A White House official said he would be having meetings and might play golf.
The rally marks an extraordinarily early start to Trump's 2020 White House bid.
He filed his re-election papers with the Federal Election Commission just five hours after being sworn in as last month.
His predecessor Barack Obama filed the same form in April 2011, more than two years into his first term as president.
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