US real estate mogul and reality television star Donald Trump has announced he will seek the Republican nomination for president.
"All of my life, I have heard a truly successful person, a really successful person, and even a modestly successful person, cannot run for public office, just can't happen," Trump said. "Yet that's the kind of mindset you need to make this country great again.
"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again."
He is the 12th high-profile Republican to enter the 2016 race, with more to come in the weeks ahead.
Trump made the announcement at the Manhattan tower that bears his name, giving a rambling speech that wandered from foreign policy to President Barack Obama's healthcare overhaul to his own achievements in business.
In his well-known bombastic style, he mixed boasts about his wealth with promises to defeat effortlessly the Islamic State group and negotiate trade deals with China.
"Sadly, the American dream is dead," Trump said. "But if I get elected president, I will bring it back bigger and better and stronger than ever before, and we will make America great again."
But it was a speech that drew immediate scorn online from a series of Republicans who fear Trump will turn an otherwise serious primary contest into a circus.
"I just apologised to my toddler for bringing him up in a country where Donald Trump runs for Prez (sic), gets better than 2% in the polls," veteran Republican strategist Liz Mair tweeted.
Republican operative Brendan Buck, who previously worked on Mitt Romney's presidential campaign and now works for Representative Paul Ryan, tweeted: "Who do I blame for Trump running for president. Whose fault is this?"
The Democratic National Committee was just as sarcastic on Twitter: "He adds some much needed seriousness that previously been lacking from the GOP field, and we look forward (to) hearing more about his ideas for the nation."
Trump has teased presidential runs before but has always backed out. In preparation for the 2016 campaign, Trump decided not to renew his contract with NBC for his reality show The Apprentice. He cannot appear on the network and run for president at the same time.
After forming a presidential exploratory committee in March, Trump has also hired political operatives on the ground in Iowa, New Hampshire and South Carolina. He has been a frequent visitor to the early voting states in recent months, and is currently doing just well enough in early public opinion polls to earn a place on stage at the first event in August.
"Selfishly, the networks would put me on because I get great ratings," Trump recently said.
He is now required to release a personal financial disclosure that would reveal intimate details about his personal finances. The disclosure will include his net worth, sources of income, liabilities and assets, as well as the same information for his wife and dependent children.
Trump said today he is ready to do so, pegging his net worth at roughly $9 billion.