Former New York City Mayor Michael Bloomberg officially announces presidential run

Former New York City Mayor Michael Bloomberg formally announced he is running for president, The Associated Press reported Sunday.

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Bloomberg, 77, wrote a letter on his campaign website, laying out a more moderate vision for the country, calling himself as "a doer and a problem solver -- not a talker."

"I’m running for president to defeat Donald Trump and rebuild America," Bloomberg wrote on his website.

In a video to kick off his candidacy, Bloomberg presented an outline of what he will focus on during the campaign, The Washington Post  reported.

Bloomberg's campaign has made more than $30 million in television advertising reservations, the Post reported, with the advertising blitz to begin Monday.

Bloomberg also announced a $100 million ad campaign to criticize Trump in key battleground states and a $15 million voter registration effort in those same states, the newspaper reported.

Bloomberg's wealth has been estimated at more than $50 billion, The New York Times reported.