UNITED STATES: US President Donald Trump lashed out Friday at what he called a fresh threat against the country's identity, taking aim at domestic "radicals and extremists" on the eve of America's 250th birthday.

In a speech dripping with patriotism, Trump lauded American exceptionalism and praised its past leaders, speaking at Mount Rushmore with its giant carved heads of four of his legendary predecessors.

But he added at the foot of the iconic monument: "As we approach this magnificent anniversary, we see our American identity under a renewed attack."

He charged that there was "a resurgence of the communist menace in our land."

It is a theme that Trump has repeatedly hammered home in recent weeks, as the anti-establishment left of the Democratic Party carried a surge of US primary victories.

The president has cast the rise of the left ahead of November's midterm elections that "communists" are on the rampage, posing a major "threat" to the country.

'Undeniable attempt'

Trump said Friday: "In recent years there's been an undeniable attempt to change this exceptional character, to beat the American spirit out of us, alienate us from our history."

While his language fell short of the more violent anti-immigrant rhetoric he has regularly wielded in past speeches, the underlying message was clear enough.

"You do not have to be born here, but you do have to love what we have built," he said.

The location of Trump's speech -- a landmark upon which many suspect he would like to see his own face carved into rock -- strikes a fitting image for a president who views himself as being one of the greats.

Trump's supporters have even introduced legislation to have his likeness chiseled beside those of George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt.

On July Fourth, Trump will hold a campaign-style political rally on the National Mall in Washington, along with flyovers by military jets and what he has billed as the world's biggest fireworks display.

US Turns 250

Trump says American identity under 'renewed attack' as US turns 250