KEYSTONE, South Dakota — President Donald Trump officially launched the United States' 250th anniversary celebrations with a patriotic address at Mount Rushmore, praising America's history while delivering a forceful warning about what he described as the growing threat of communism inside the country.

Speaking beneath the iconic granite monument featuring Presidents George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt, Trump called on Americans to protect the freedoms established by the nation's founders and preserve what he described as the country's unique identity.

"Communism is a mortal threat to American liberty," Trump declared. "It is the greatest threat to our country, including World War I, World War II, Pearl Harbor or even 9/11." The remarks quickly transformed what began as a patriotic celebration into a highly political speech centered on domestic ideological battles.

The president argued that communist ideas are experiencing a resurgence in the United States, blaming progressive Democrats and some immigrants whom he claimed embrace values incompatible with the nation's traditions. Trump insisted that America "will never become a communist country" and urged citizens to defend the country's culture, history and constitutional principles.

Throughout the address, Trump celebrated American exceptionalism, highlighting the country's military strength, constitutional freedoms, religious liberty, free speech and the right to bear arms. He also encouraged Republicans to pursue election law reforms ahead of November's midterm elections, tying political success to what he described as safeguarding American democracy.

The speech marked a notable departure from the traditionally bipartisan tone associated with Independence Day commemorations. Political observers noted that Trump's repeated references to communism echoed the rhetoric of the 1950s Red Scare, when suspected communists were widely investigated, blacklisted and persecuted across the United States.

Mount Rushmore itself added symbolic weight to the event. Trump has previously expressed admiration for the presidents carved into the monument and has publicly suggested that he hopes his own legacy will someday be remembered alongside theirs, although experts have dismissed the possibility of altering the historic memorial.

The Mount Rushmore ceremony officially opened America's semiquincentennial celebrations, with additional Independence Day events, concerts and fireworks scheduled throughout Washington, D.C., and across the country. At the same time, the anniversary highlighted the nation's continuing political polarization as the United States prepares for another closely watched midterm election cycle.