PHILADELPHIA — 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.

While President Donald Trump attended a military parade he ordered on his birthday to recognize the 250th anniversary of the U.S. Army in Washington, D.C., thousands of people in the Kansas City metro area flexed their First Amendment right Saturday to voice their opposition to polices of the Trump administration during the “No Kings” national day of defiance.

An estimated 10,000 people were in attendance at the “No Kings” rally that began in Pioneer Park and marched north through the downtown area, the Salt Lake City Police Department said. Gunfire was heard at around 8 p.m., with video posted online showing protesters fleeing in terror.

Before you let your voice be heard, advocacy and civil right groups stress the importance of being prepared before you go. And knowing your rights.

Far-right groups are humming with talk of potential violence ahead of massive “No Kings” Day demonstrations that are expected to attract millions of protesters Saturday, according to The Wall Street Journal.

Here's how to stay safe and what to know about your rights if you get arrested, detained or encounter tear gas during Houston's No Kings Day protest.

Coordinated "No Kings" protests are happening from coast to coast, part of a "national day of peaceful protest" against the Trump administration, expected to draw millions. Protesters in some areas braved wet weather to raise signs and chant slogans supporting the rights of immigrants and criticizing what they see as Trump's power grab.

"No Kings" protests against the Trump administration are taking place today in and around New York City as part of nationwide demonstrations. Fifth Avenue was closed to traffic from 42nd Street to 23rd Street in Manhattan as protesters marched from Bryant Park.