Mayor Bloomberg’s nationwide campaign against illegal guns is taking to the airwaves, with the launch of a targeted television and Internet advertising campaign aimed at shaming Congress into repealing an amendment restricting access to information about guns used in crimes.

Flanked by New Jersey mayors and police officers at City Hall in Jersey City yesterday, Mr. Bloomberg said it was a coincidence he was announcing the ad campaign and the addition of 27 new mayors to his coalition two days after 32 people were shot dead at Virginia Tech. There are now 214 mayors in the coalition.

The tragedy is a terrible reminder of what can happen when guns wind up in the wrong hands, Mr. Bloomberg said. He noted that violent crime is on the rise throughout America.

“In fact, about 30 Americans are murdered every single day,” he said. “Just think about all of the press, all of the publicity, all of the thought that we’ve given to the terrible tragedy at Virginia Tech. The same thing really does happen, if you combine our country together, every single day.”

The television ads, which will debut Sunday morning during political talk shows, feature the chief of police of Chaska, Minn., Scott Knight, who talks about how the Tiahrt Amendment, named after Rep. Todd Tiahrt of Kansas, impedes his ability to fight gun crime.

New Jersey is considered a key battleground area because Rep. Rodney Frelinghuysen of New Jersey is the ranking minority member of the House Appropriations Committee’s commerce, justice, science, and related agencies subcommittee, which is considering the Tiahrt Amendment.

“The best tool that police have to protect our residents and themselves from illegal guns is trace data,” Mr. Bloomberg said.

Mr. Bloomberg’s campaign has drawn the ire of the National Rifle Association, which this month put a cartoon of the mayor, who is Jewish, on the cover of its magazine that featured octopus tentacles creeping out behind him.

Octopuses are often used as anti-Semitic symbols in the Arab press, but a spokeswoman from the Anti-Defamation League, Myrna Shinbaum, said the NRA cover was not deemed anti-Semitic because it doesn’t include Jewish symbols.

A spokeswoman for the NRA, Rachel Parsons, said any resemblance to any anti-Semitic symbol is inadvertent and unintentional.

“We encourage anyone who thinks otherwise to read the cover of the magazine,” she said. “The caption describes the reason for the illustration.”