NBC News- A weekend of protests over the inauguration and presidency of Donald Trump began Thursday night with police in the nation's capital using pepper spray on protesters demonstrating outside a pro-Trump event.

Hundreds rallied outside the National Press Club, where the event billed as DeploraBall was being held on the eve before Trump is sworn in as president Friday. Some demonstrators set off smoke devices in the middle of the crowd, and police in riot gear blocked entrance to the event.

"Impeach the predatory president," read one of two messages projected onto the building's façade. Crowds chanted "Nazi scum" at those who entered. Some of the protesters were with the group Refuse Fascism.

Police said they arrested a 34-year-old D.C. man near the event and charged him with conspiracy to commit an assault and were looking for two others, NBC Washington reported.

At one point, demonstrators burned a Trump hat. An inflated elephant — a commonly used mascot for the Republican Party — was displayed adorned by a banner with the word "racism" on it.

The demonstration in D.C. was one of several held throughout the country in opposition to Trump, including a "unity" demonstration outside Trump International Hotel in New York, which was attended by actors Robert De Niro, Sally Field and Mark Ruffalo.

They could be a small taste of what's to come. Dozens of groups have been planning for weeks to descend on D.C. during inauguration week and make their opposition to the incoming president known.

Some, like the ANSWER Coalition — which stands for Act Now to Stop War and End Racism — are planning to be a vocal and visible presence near the inauguration, but not to engage in any potentially illegal activities.

Others, like the pro-marijuana legalization group DCMJ, are advocating on behalf of a specific policy priority. Marijuana use is legal in Washington, and DCMJ plans to pass out thousands of marijuana cigarettes, or joints, for supporters to smoke during Trump's inaugural speech, to show support for legalization.

A protester has her eyes doused with water after being pepper sprayed by police outside of the DeploraBall at the National Press Building in Washington on Jan. 19. Patrick Smith / Getty ImagesBut still others hope to create some chaos. That's the case with Disrupt J20, a group organizing a series of protests with the direct aim of disrupting the inauguration.

"We must take to the streets and protest, blockade, disrupt, intervene, sit in, walk out, rise up, and make more noise and good trouble than the establishment can bear," reads the group's manifesto.

And the biggest protest, set for Saturday, could be history-making. That's when the Women's March on Washington is expected to draw 200,000 protesters to the streets of D.C., a number that Inaugural Historian Jim Bendat said could break records.

"It's quite noteworthy. If they get those kinds of numbers, it will far exceed any previous inaugural protest," he said.

Overall, the National Park Service has approved 22 permits for First Amendment events ranging in size from 50 to 200,000 people for inauguration week. Though many protest organizers state outright they have no plans to break laws or create altercations, city and federal law enforcement agencies have been working together in preparation for every security concern.

D.C. Mayor Muriel Bowser has said more than 3,000 police officers from other regions and 5,000 National Guardsmen will be on-hand to help secure the parade route.

"Security is my greatest concern," Republican Sen. Roy Blunt, chairman of the Joint Congressional Committee on Inaugural Ceremonies, has said. "No question that on inaugural day, this would be the most appealing target in the world."

At Thursday's D.C. protest, an organizer said police acted aggressively and tried to "cattle corral" demonstrators, and hoped the use of pepper spray wouldn't dissuade others from turning out this weekend. D.C. Anti-Fascist Coalition organizer also said another, rowdier group joined Thursday's protest.

"This did not go how we expected it to," she said.

Stefan Johnson, a Trump supporter who came by to watch Thursday's demonstration, said it was mostly civil. "There was a little bit of passion on their side which is somewhat understandable, I guess," he said.

Johnson and others with him had some conversations with protesters. "The same old thing: he's a racist, he's sexist, he hates immigrants, that's about it," Johnson said.

A Twitter account for the DeploraBall event mocked protesters, posting a video of crowds chanting "F--- Trump!" with their own message: "Shouting won't change tomorrow's outcome … can't wait to say president @realDonaldTrump."