NEW YORK ( CNN ) -- An investigation commissioned by the city of New York found private gun vendors selling weapons to buyers who admitted not being able to pass background checks , breaking federal law , a report released Wednesday says . It is illegal for unlicensed sellers to sell a gun if there is reason to think the buyer would fail a background check . The sales were made at seven gun shows in Ohio , Tennessee and Nevada , the report says . Hired investigators with hidden cameras were able to purchase guns from private sellers after announcing to the vendors they could not pass a background check , it says . Nineteen of the 30 private sellers the undercover investigators dealt with failed the integrity test , according to the report . The law does not require private unlicensed sellers at gun shows to do background checks on their customers . However , it is a federal felony for unlicensed sellers to sell a gun if they have a reason to believe the buyer would fail a background check . There were no arrests and no lawsuit were filed . `` Closing the gun show loophole has nothing to do with the Second Amendment , '' Mayor Michael Bloomberg said in a news conference Wednesday . `` It is basic law enforcement , plain and simple . '' He said he does not want to shut down gun shows but to change the law . He cited a 2000 study from the then-Bureau of Alcohol , Tobacco and Firearms saying 30 percent of guns involved in federal illegal gun trafficking investigations are connected in some way to gun shows . The figure is disputed by gun proponents . `` We believe anyone who breaks the law should be arrested , prosecuted and punished , '' the National Rifle Association said in a statement supplied to CNN . `` Instead of working with law enforcement to bring those who may have broken the law to justice , Mayor Bloomberg chose to use this information for a press conference . Bloomberg 's priorities are clearly media first , justice later . '' But Bloomberg has support from some in Washington , including Sen. Frank Lautenberg , D-New Jersey . `` This investigation reveals how easy it is for criminals and even terrorists to purchase firearms at gun shows and is further proof that we must close the gun show loophole , '' Lautenberg said in a written statement .
Sales made at gun shows in Ohio , Ohio , Tennessee , report says . 30 of 30 private sellers in sting failed the integrity test , according to the report . Closing gun-show loophole `` is basic law enforcement , '' CNN mayor says . It `` has nothing to do with the Second Amendment , '' said Mayor Michael Bloomberg .