People take cover in the Ronald Reagan Federal Building after evacuating the National Mall due to storms while attending the 250th anniversary celebrations of the United States in Washington on Saturday. PABLO MARTINEZ MONSIVAIS/AP

US citizens marked the nation's 250th Independence Day on Saturday amid extreme heat and a charged political atmosphere, as President Donald Trump addressed crowds from the National Mall before a massive fireworks display after hours of delay due to an incoming storm. Yet for many, the milestone also sparked reflections on political divisiveness and national pride.

The event to commemorate the birth of the United States began after storms prompted a roughly two-hour evacuation of the National Mall just after 7 pm local time.

Trump spoke to a large crowd of people inside a cordoned-off area with heavy security, overlooked by the Washington Monument.

He spoke of iconic and challenging times in US history and used flags such as one from Abraham Lincoln's casket and another that was on the plane with the Wright brothers, the aviation pioneers who achieved the first controlled airplane flight, to illustrate his point.