At least 10 people were arrested and four police officers needed medical attention as some revelers got rowdy at the annual Santa Con bar crawl in Hoboken, according to the city's police chief.

According to the chief's Twitter account, two officers were hospitalized, including one with a broken thumb and another who had been punched in the face. Two suspects were charged with aggravated assault on officers.

Two more officers required treatment for exposure to combatants' blood, and other arrests were made for possession of marijuana and disorderly conduct, according to Ferrante.

Police were out in full force as the annual event got underway. Chief Ken Ferrante told News 12 earlier in the day that a handful of summonses has been issued, but he later tweeted that "activity has picked up rapidly since 4:30 p.m."

The mayor says 10 bars took part this year, down from 30 last year. Some even shut down due to overcrowding.

Ferrante has been vocal about his position against Santa Con.

"I get emails, I get direct messages, people stop me on the street, they say on this day it's hard for them to explain to their 4-year-old, 5-year-old why Santa or Mrs. Santa are acting that way," Ferrante says. "And that's why I don't like this event."

Ferrante said patrols could top 100 officers during the height of the event.