Photos: Thousands of demonstrators flood downtown Milwaukee

Thousands of anti-Trump protesters flooded downtown Milwaukee, Monday, on the first day of the Republican National Convention (RNC), demonstrating what they're calling "the racist and reactionary agenda of the Republican Party."

Demonstrators, surrounded by heavy police presence, held signs reading "Lock him up!" "Free Palestine" "Ban bombs, not books" and "Stop Trump and Racist Republicans." The rally was organized by the "Coalition to March on the RNC," whose agenda "is the opposite of everything the Republicans stand for," according to its website.

"Our Coalition opposes racism and war, reaction and genocide. We are supporting immigrants' rights, supporting women's freedom to choose, holding up LGBTQ freedom, and calling to give workers raises and lower prices for staples like food and drinks, gas, and rent. We want peace, justice, and equity!" the website states.

The day, billed as a family-friendly event, started off with a group of about 100 protesters, including activists from the Minnesota Immigrant Rights Action Committee about 2 miles away at Red Arrow Park. Democratic Wisconsin state Rep. Ryan Clancy spoke during the rally.

Around noon, about 2,000 protesters from a national coalition of groups and unions joined to march to Fiserv Forum, the site of the convention.

At one point, "a group of demonstrators got in an argument with counter-protesters who denounced LGBTQ+ rights, Muslims, Black Lives Matter and women," the Associated Press reported.

Here’s a look at the protests on day one of the RNC: