The United States celebrates its 250th anniversary; Trump expresses alarm about American identity.

Happy birthday America? The United States celebrates its 250th anniversary on Saturday, a historic milestone reached at a time when the country is deeply divided, with Donald Trump determined to claim the leading role in Washington.

This particular "Independence Day", 250 years after the signing of the Declaration of Independence in Philadelphia (east) marking the break of thirteen colonies with the British Crown, comes in the midst of a suffocating heat wave in the eastern United States.

In Washington, temperatures are forecast to reach over 38°C on Saturday, and combined with humid air, the perceived temperature is expected to reach nearly 43°C. The traditional Fourth of July parade scheduled for Saturday morning in the nation's capital has been canceled due to this risk of extreme heat, organizers announced.

This expected heatwave is far from discouraging or changing the plans of Donald Trump, who has done everything to transform this anniversary of the United States into a celebration of himself.

The US president is scheduled to hold a political rally on Saturday evening (starting at 01:45 GMT on Sunday), resembling an election campaign event, on the vast green expanse of the National Mall in the heart of the American capital, before what he is touting as the world's largest fireworks display – 850,000 rockets for 40 minutes!

"It's going to be about 107°F (41°C) and I'm going to give a really long speech - just to show that I can do anything," he said during the week.

He also promised flyovers and military bands to perform patriotic music, American classics, "as well as my playlist".

- "New offensive" -

On the eve of the national holiday on Friday evening, at the foot of the iconic Mount Rushmore (north), Donald Trump claimed that American identity was suffering on its own soil what he described as a "new offensive" from "radicals and extremists".

In an ultra-patriotic speech, he painted a picture of the American "miracle" and heaped praise on four of his presidential predecessors whose granite faces were displayed above him - George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt.

Before warning of "a resurgence of the communist threat on our soil".

He has repeatedly used this rhetoric in the lead-up to the crucial midterm elections in early November, following a series of victories for left-wing Democratic candidates in the primaries. Republicans fear that the president's unpopularity will cost them control of Congress.

Donald Trump also referred to "radicals and extremists" who "attack our incredible history at every opportunity" and an "undeniable attempt to make us lose our American spirit."

About ten days ago, the Republican president already made an appearance on the National Mall in the capital as part of the 250th anniversary celebrations, on the eve of the opening of his "grand fair." Since then, it has been notable mainly for its sparse visitors and empty booths.

- "Fed up" -

As the country remembers its two and a half centuries of history, triumphs and tragedies, slavery and freedom, civil war and world wars, a recent Quinnipiac University poll shows that 61% of Americans believe the United States is not living up to the ideals set forth in the Declaration of Independence of 1776.

"I'm fed up with the way this country treats people. Fed up with the way this country treats its neighbors. Fed up with a whole lot of things," Johnny Presley, an artist based in Los Angeles (west), told AFP.

Karisa Tavassoli, a 31-year-old Iranian-American teacher in Atlanta (southeast), focuses on something else. "I am safe, there is freedom of expression, freedom of religion, I can dress as I want as a woman. There are many problems here, but we have something very special that deserves to be protected," she emphasizes.

Alonzo Coby, an architect and member of the Shoshone-Bannock Native American tribe, interviewed by AFP in Blackfoot, Idaho (northwest), said he was "happy to celebrate this event with the United States." "But," he added, "I want people to remember that Native Americans have been here for much longer than 250 years."