Responding to calls for a crackdown on city nightlife, the New York State Liquor Authority is refusing to issue new licenses to bars and clubs in certain areas of Manhattan for the rest of the year.

The moratorium announced yesterday follows the recent high-profile murders of two young women after late-night partying. It comes as the state Senate is preparing to hold a hearing today in Lower Manhattan on the enforcement of nightlife regulations. The City Council has planned a security summit for later this month.

The moratorium applies to bars, clubs, and cabarets seeking to open within 500 feet of three or more existing nightlife establishments, likely meaning a freeze on new nightspots in the trendy neighborhoods of Chelsea, the meatpacking district, and the Lower East Side.

“This moratorium will give the SLA time to thoroughly analyze our policies, procedures, and applications related to nightclubs and bars,” the authority’s chairman, Daniel Boyle, said in a statement.The announcement was made after a unanimous board vote yesterday.

The liquor authority also said yesterday that it would convene a task force to examine the Alcoholic Beverage Control Law and would launch sweeps of what it called “problem nightspots” in the city.

Issued with little warning yesterday, the moratorium faced a swift outcry of criticism from key players in the nightlife industry.

“It’s a gross overreaction to a problem that could have been solved through conversation and negotiation, rather than mandate,” the owner of Lotus on 14th Street in the meatpacking district, David Rabin, said. Mr. Rabin called the license ban an “unnecessary atomic bomb when a surgical strike would have served more appropriately.”

An attorney for the New York Nightlife Association, Warren Pesetsky, a former general counsel for the liquor authority, attacked the move as overly broad. “The vast majority of the industry are law-abiding businesspeople,” Mr. Pesetsky said.

The authority’s decision drew praise from several politicians who have called for more restrictions on nightlife and who have criticized the SLA for a lack of enforcement when it comes to the city’s clubs and bars. “I am glad that the SLA is taking our criticism seriously and is taking action,” the chairman of the state Senate Committee on Investigations and Government Operations, Nick Spano, said. Mr. Spano, a Republican of Yonkers, is chairman of today’s hearing. He said he thought the moratorium was appropriate.

The City Council speaker, Christine Quinn, who is spearheading a summit on nightlife security later this month, also praised the liquor authority for acting, but she would not comment yesterday on its specific initiatives. Of the moratorium, she said only that it was “an intriguing idea.”

Mayor Bloomberg’s spokesman, Stuart Loeser, said the mayor “welcomed any renewed focus” on the city’s needs from Albany, but he would not say whether Mr. Bloomberg supported the moratorium on liquor licenses.

The crackdown by the liquor authority could deepen a rift that has opened between the nightlife industry and some city and state officials following recent incidents at city bars and clubs.

In February, a 24-year-old student at John Jay College of Criminal Justice, Imette St. Guillen, was raped and murdered after a night out drinking in the city. She was last seen at The Falls in SoHo, and a bouncer at the bar, Darryl Littlejohn, was charged in her death. Littlejohn had prior felony convictions, and the liquor authority has since shuttered the bar.

Last month, the mayor signed the “bouncer bill,” which makes it easier for city officials to shut down bars and clubs that don’t perform background checks on their security guards.

St. Guillen’s murder was followed in August by the slaying of Jennifer Moore, an 18-year-old from New Jersey who was found killed after a night out at a Chelsea nightclub.

After the Moore murder, Ms. Quinn, whose district includes Chelsea and the Meatpacking District, announced the nightlife summit as well as legislation aimed at boosting safety and curbing underage drinking at clubs and bars. The proposals include requiring nightclubs to install surveillance cameras and ID scanners.

An attorney with the New York Nightlife Association, Robert Bookman, had praise for Ms. Quinn and said he was optimistic about this month’s summit, but he criticized other officials for political grandstanding that he said could hamper the city’s reputation for nightlife. “The atmosphere is clearly poisonous,” Mr. Bookman said. The association is pushing for increased enforcement regarding the sale of fake IDs, as opposed to just targeting bars that fall for them. “You’ve got to stop passing laws where businesses are the sole law enforcers,” he said.

Requiring security cameras in the clubs wouldn’t help, Mr. Bookman said, as most of the problems occur outside. The association also wants its members to be able to hire off-duty police officers as security guards, which the Police Department has long opposed.

Ms. Quinn, in an interview before the liquor authority announced its moratorium, said she respected the “economic contribution of the nightlife industry” and hoped to consider a wide range of possible solutions at the summit. But she did not back off her proposals. “We have a problem in this city,” she said. “You can’t ignore that. We have an obligation in city government to try to protect New Yorkers.”