Donald Trump to formally announce re-election bid on June 18 in Florida

Trump defeated Democrat Hillary Clinton in 2016 elections to win the White House

US President Donald Trump has said that he would formally announce his bid for re-election at a June 18 rally in Florida - a state that was key to his victory in 2016.

Trump's wife Melania, Vice President Mike Pence and his wife Karen will also be part of the evening event in Orlando at the Amway Center arena, Trump said on Twitter on Friday.

"I will be announcing my Second Term Presidential Run... on June 18th in Orlando," he said. "Join us for this Historic Rally!"

Trump has made it clear since taking office that he planned to run again in 2020, has held multiple campaign rallies and has already raised tens of millions of dollars.

When he speaks to his supporters, he often refers to his six remaining years in power -- not the 18 months left in his first term.

Trump will launch his campaign against the backdrop of mounting Democratic calls for his impeachment, including by several of the nearly two dozen members of the opposition party seeking to unseat him.

For now, the 72-year-old billionaire Republican leader has focused his energy -- and fiery criticism -- on Democratic frontrunner Joe Biden, the 76-year-old former vice president.

Biden, a six-term senator before serving as number two to president Barack Obama, has taken a substantial lead in early polling. Trump has referred to him as "Sleepy Joe" -- and even "SleepyCreepy Joe."

Biden styles himself, like Trump, as an ardent defender of working class Americans -- someone who can win back the Midwestern, white, male blue-collar voters who went for the Republican in 2016.

Trump defeated Democrat Hillary Clinton to win the White House.

Three weeks ago, Trump said the Democratic presidential primary would come down to a race between Biden and independent Senator Bernie Sanders, who lost the nomination to Clinton in 2016.

"Looks to me like it's going to be SleepyCreepy Joe over Crazy Bernie," Trump tweeted. "Everyone else is fading fast!" In the announcement of his presidential run in April, Biden said Trump had "fundamentally altered the character of this nation." The scene of Trump's announcement is no accident: Florida is a major prize for any presidential candidate, and traditionally a battleground state.

In 2012, Obama bested Mitt Romney in the Sunshine State by less than one percentage point. In 2016, Trump beat Clinton there by a bit more than one point.

The election will take place on November 3, 2020.