PHILADELPHIA (AP) — Cities large and small were preparing for major demonstrations Saturday across the U.S. against President Donald Trump, as officials urge calm, National Guard troops mobilize and Trump attends a military parade in Washington to mark the Army’s 250th anniversary.

Brevard County Sheriff Wayne Ivey warned that "peaceful protests are part of our democracy, but the key word in that is 'peaceful.'"

Ahead of Saturday's "No Kings" protests, Florida officials issued aggressive warnings, with one sheriff threatening to kill violent demonstrators and the attorney general encouraging drivers to run over protesters who block roads.

As a military parade rolls through Washington, DC, on Saturday – President Donald Trump’s birthday – millions of Americans are expected to protest in what organizers predict will be the strongest display of opposition to Trump’s administration since he took office in January.

Protests are taking place in Florida and nationwide on June 14, the same day as the military parade in Washington DC.

Dozens of protests and rallies against the Trump administration are set to take place in the San Francisco Bay Area this weekend, as part of the nationwide "No Kings" movement.