Live updates on NYC's America 250 celebrations

The Sail4th 250 parade has begun in New York City, which is expected to draw large crowds to the city's waterfront.

Many of the participating vessels, known as Class B tall ships, have been arriving in New York Harbor over the past several days.

Saturday's Sail4th 250 parade began at 7 a.m. ET, with ships sailing north on the Hudson River from the Verrazzano-Narrows Bridge to the George Washington Bridge.

Leading that event is America's Tall Ship, the U.S Coast Guard Cutter Eagle.

The larger ships are anchored near Sandy Hook as sailors from 20 nations prepare to sail up the Hudson.

The event is expected to attract thousands of spectators as New York joins the nationwide celebration of the nation's semiquincentennial.

Officials say security checkpoints and screenings will be in place for designated viewing areas during Saturday's Sail4th 250 festivities along the Hudson River.

President Donald Trump kicked off a weekend of celebrations for America's 250th birthday with a speech at Mount Rushmore on Friday.

Ahead of the trip, the White House suggested Trump could be an "addition" to the mountain where the faces of George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln are etched.

"There would be no better addition to the iconic Mount Rushmore than the 45th and 47th President of the United States, Donald Trump," White House spokesperson Taylor Rogers said in a statement to ABC News.

Trump has previously mused about putting his likeness on the granite peak. He called it a "good idea" on social media in 2020. But so far in his second term, there's been no significant movement toward making that a reality.

The White House did not respond to questions about whether there are actual plans to add the president's likeness to Mount Rushmore and, if so, in what capacity.

Trump flew to Keystone, South Dakota, on the newly retrofitted Air Force One 747, a gift from the Qatari royal family. The president used the jet for the first time earlier this week for a trip to North Dakota for the opening of the Theodore Roosevelt Presidential Library.

Upon his arrival, Air Force One conducted a flyover over Mount Rushmore National Memorial in South Dakota ahead of the president's remarks.

The Mount Rushmore festivities also include performances by military bands and tributes to the Armed Services. It will culminate in a large fireworks display, the first fireworks show at the national memorial in years, according to the National Park Service.

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"World News Tonight" anchor David Muir kicked off ABC News' celebration of America's 250th birthday by climbing up through Lady Liberty's right arm to reach the torch, standing over 300 feet in the air.

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Fleet Week is an iconic part of summer in New York City, and this year, it coincides with Sail4th 250 celebrations.

Sandra Bookman has a look at this year's festivities.

Sandra Bookman has a look at this year's festivities.