New Year's Eve brought out thick crowds of revelers, but smaller groups used the occasion to stage protests against police brutality as police noted heightened threats against officers.
The protests are a continuation of the outcry against police brutality that came after the grand jury decisions in the deaths of Michael Brown in Ferguson, Missouri, and Eric Garner in New York City.
In Boston, activists held a "die-in" during First Night, Boston's popular New Year's Eve celebration, the Associated Press reported. The demonstration was staged in front of the Boston Public Library during the evening. Others held signs that read "black lives matter."
Police reported no arrests or disruptions to nearby festivities.
In New York, protesters intended to march from Union Square towards the huge New Year's celebration in Times Square. Other protesters were advised to take signs into Times Square early and pull them out when the ball drops at midnight, as well as chanting "We Can't Breathe!" and "Black Lives Matter!" at the top of every hour.
Two NYPD officers were shot and killed last week and the NYPD has assessed 70 threats made against police officers after the Brooklyn shooting, which led to 16 arrests.
The National Guard had an "increased presence" at transport hubs in New York City. Gov. Andrew Cuomo did not specify exactly how many guardsmen would be in New York City but did say that one unit, the 22-member 24th Civil Support Team, will continue their regular support of the NYPD to deal with chemical, biological or radiological hazards.
The National Guard has boosted its security at New York City transit hubs every year since the 9/11 terror attacks.
A group of about 75 protesters marched from downtown St. Louis to the police headquarters today while chanting outside the entrance. Several people stormed the building and five people were arrested for trespassing and one was arrested for third degree assault after an incident with a city marshal in the building.
Photos posted on social media showed protests in Ferguson, Missouri, today.
A press officer for the Los Angeles Police Department told ABC News that they had seen social media reports about plans for protests, but Officer Drake Madison said that were are no plans to increase their patrols as a result of the protests. "We're always available and have enough resources available anyway," Madison said.
ABC News' Aaron Katersky contributed to this report.