Ten people were arrested at Hoboken's Santacon on Saturday, including one man who punched a police sergeant in the face, the police chief said on Twitter.
Chief Ken Ferrante was tweeting real-time updates of the police response to SantaCon, a bar crawl in which participants dress in Santa costumes.
Two officers were hurt in a fight near Cadillac Cantina, he said. One of the officers was hospitalized with a dislocated thumb, the other was punched in the face.
Two men, ages 22 and 23, were charged with aggravated assaults on officers, Ferrante said.
Two other officers were treated after they were exposed to blood at a brawl at Johnny Rockets, the chief said.
"That's 4 officers needing medical aid, & some wonder why I condemn this day!" Ferrante tweeted.
The other people arrested faced charges including disorderly conduct, possession of marijuana and driving while intoxicated, he said. Police also issued summonses for public urination. One man was charged with resisting arrest after leading police on a foot pursuit, the chief said.
About 100 officers would be mobilized for SantaCon, Ferrante said.
Last year, 17 people were arrested and a woman allegedly punched a police officer in the face.