Protesters are gathering nationwide, including Colorado, as President Trump attends a parade commemorating the Army's 250th anniversary on his 79th birthday.

Denver police arrested 17 protesters on suspicion of graffiti, interference with law enforcement, obstructing streets, throwing objects and assault, according to the police department.

Denver police now say officers arrested 18 people during protests near downtown on Tuesday over immigration enforcement. Things started peacefully at the Colorado State Capitol. At one point, protesters attempted to walk onto Interstate 25,

Dozens of Regional Transportation District routes were detoured or delayed throughout metro Denver on Saturday as thousands of Coloradans gathered for “No Kings” protests.

Denver Mayor Mike Johnston said the city doesn’t need the National Guard or federal enforcement to handle demonstrations and protests, and will oppose it.

Eighteen people were arrested Tuesday night after protesters got into confrontations with Denver Police during demonstrations, prompting Mayor Mike Johnston to warn that violent actions could invite the type of federal intervention President Donald Trump has threatened to deploy in cities.

The parade, honoring the Army’s long-planned 250th anniversary celebration and coinciding with Trump’s 79th birthday, is set to step off from the Lincoln Memorial under the threat of stormy weather in Washington and protests around the country tied to a turbulent week of immigration enforcement that has involved military deployment in Los Angeles.

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.