Tossing cold water on what’s billed as one of the biggest barhopping nights of the year, Buffalo police are warning Chippewa Entertainment District bar owners that underage drinking will not be tolerated tonight or any other night.

The cops mean business.

Five bars were cited Saturday night, accused of serving alcohol to 19-year-old decoys during a sweep of many of the downtown strip’s establishments.

House lights were flipped on, music turned off and inspections conducted to make sure all was in order, even in bars where illegal sales had not occurred.

“The bar owners weren’t happy. It was a total surprise, but now they understand they will be held accountable for how they run their businesses,” Central District Chief Brian K. Patterson said.

In addition to city police, State Police, parole officers, federal agents and marshals, and State Liquor Authority investigators were involved in the sweep.

The Wednesday night before Thanksgiving attracts huge bar crowds because many young people who have left the area return home for the holiday, and college students have a long weekend, Deputy Police Commissioner Charles H. Tomaszewski said.

Until now, Central District officers designated individual bars for “integrity checks” during weekend nights to make sure there were no underage drinkers, but with increased incidents of violence, including two recent homicides in parking lots just off the Chippewa strip, and escalating police overtime costs in guarding revelers, Police Commissioner Daniel Derenda said stronger measures were required.

“Starting Wednesday, you’re going to see increased police visibility in the Chippewa district and throughout the city during the holiday season,” Derenda said Tuesday. “People should feel safe coming into the city to shop and go to restaurants and enjoy other activities.”

Bars accused of selling alcohol to minors Saturday were 67 West, Soho Burger Bar, Social Bar & Nightclub, King’s Court Restaurant & Bar and another bar that has not yet been identified. Four employees were charged with serving alcohol, and a fifth is expected to be arrested.

The crackdown comes nearly two months after a local law expired that allowed commingling of 18-to-20-year-olds with 21-and-above patrons in bars and clubs on Thursday nights. Some bar owners have complained about the end of Thursday night commingling, saying that the loss of cover charges from those young people has resulted in a substantial drop in revenues.

“We sent the decoys into the bars with their identification, and even though they were underage, they were allowed to enter and buy drinks,” State Police Capt. Steven C. Graap said. “Everyone knows underage people will try to go out and consume alcohol. We need to make sure these establishments aren’t facilitating or perpetuating that detrimental behavior.”

This was the first time that other law enforcement agencies joined Buffalo police in a crackdown on underage drinking at the request of the Police Department and Mayor Byron W. Brown, who applauded the collaborative effort.

“We went to 13 bars, and we would have gone to all of them, but we ran out of time,” Graap said, adding that State Police are more than willing to participate in future actions.

There are about 20 bars in the Chippewa district.

Federal marshals and members of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives also assisted, in case illegal guns were found. None were. Members of the Police Department’s Strike Force also assisted.

Bars that cater to gang members, Derenda said, have also been put on notice to stop seeking that type of clientele. Patterson said his officers recently prevented a Chippewa district bar from hosting a party for a gang.

A Chippewa area bar owner took issue with insinuations by authorities that they are irresponsible.

“We as bar owners do not need to be told we are accountable. We know we are, and this wasn’t really a total surprise. At any time this could happen,” the bar owner said, requesting anonymity. “If the police are looking to get a high-five from the community, it is good public relations for them.”

But, the bar owner added, there are bigger problems with underage drinking at Buffalo Bills games and at Darien Lake concerts.

“It is not a unique problem for us.”