A sheriff who urged Milwaukee-area residents in a radio ad to learn to handle firearms so they can defend themselves is dismissing pointed criticism from the city's mayor -- calling the mayor's response "weak" and telling Fox News "my job is to protect the public."

Milwaukee County Sheriff David Clarke Jr. stirred controversy after releasing a 30-second radio ad saying budget cuts have hurt officers' ability to respond.

"With officers laid off and furloughed, simply calling 911 and waiting is no longer your best option," he said in the ad. "You can beg for mercy from a violent criminal, hide under the bed, or you can fight back. ... Consider taking a certified safety course in handling a firearm so you can defend yourself until we get there."

Milwaukee Mayor Tom Barrett lashed out at the ad. His office said in a statement: "Apparently Sheriff David Clarke is auditioning for the next Dirty Harry movie."

Clarke, in an interview Monday with Fox News, brushed off the criticism.

"Personally I've never seen the Dirty Harry movie -- but if that's all the mayor can come up with, that's pretty weak," he said. "I think that what's going on in the city of Milwaukee on his watch is kind of, you know -- it looks like he doesn't have much to say, he doesn't have much to offer and that's okay.

"My job is to protect the public," he said.

Clarke said that with the Milwaukee area beset by burglaries and robberies, residents need to know how to protect themselves.

"We can't be everywhere all the time. Sometimes we can't be there as fast as we'd like," he told Fox News. "Once the wolf is at the door ... 911 isn't going to help you, but there are some things that you can do."

The ad has generated sharp criticism from other area officials and anti-violence advocates. The president of the Milwaukee Deputy Sheriffs' Association, Roy Felber, said it sounds like a call to vigilantism.

"That doesn't sound too smart," Felber said. "People have the right to defend themselves, but they don't have the right to take the law into their own hands."

Under Wisconsin's "castle doctrine," someone who uses deadly force against an unlawful intruder to their home, business or vehicle is presumed to have acted reasonably. A spokeswoman for the state Department of Justice said that as of this week, there are about 155,000 concealed carry permits in Wisconsin.

Barrett was beaten up several years ago by someone with a tire iron, and Clarke said he thought that would make the mayor "a lot more sensitive to people being able to defend themselves in such instances. A firearm and a plan of defense would have come in handy for him that day."

But Jeri Bonavia, executive director of Wisconsin Anti-Violence Effort, said Clarke took a dangerous position with his ad. She pointed to the case of George Zimmerman, a neighborhood watch volunteer in Florida who fatally shot an unarmed 17-year-old following an altercation. Zimmerman has pleaded not guilty to second-degree murder, claiming self-defense under Florida's "stand your ground" law.

"I feel like this is such an irresponsible thing for our chief public safety officer of a county to do," Bonavia said. "I think he owes this community an apology. And if he really believes that he's not capable of providing for our public safety he should get a different job."

The Associated Press contributed to this report.