Updated

Moviegoers may soon get a 30-second lesson in gun safety along with their popcorn.

Beginning May 18, a trailer featuring Arizona Sen. John McCain talking about gun safety will play on 2,500 screens in 44 states.

In the ad, McCain, standing on a school playground, urges adults to keep guns locked up and encourages children to tell a parent or a teacher if they hear someone talk about using a gun.

"Because what you do today may save a friend's life tomorrow," McCain says.

"In this great country, owning a gun is a right that carries responsibilities," the former GOP presidential candidate says.

Americans for Gun Safety, a nonprofit group, is paying $250,000 to run the ad for one month in 210 cities.

Jonathan Cowan, president of Washington-based group, said the message is being taken to movie theaters to catch the attention of kids and parents as the summer movie season kicks off.

Cowan said the group was also focusing on movie to remind children "that the use of guns as entertainment in movies is not something anyone wants to see in real life."

American for Gun Safety estimates that 40,000 children bring guns to school each year.

The group is also launching a firearms safety program online.

The ad will appear in every state except Alabama, Alaska, Connecticut, Idaho, Hawaii and Utah.

Jim Baker, chief lobbyist for the National Rifle Association, said the message of the movie trailers is a good one.

But he said it belies Americans for Guns Safety's broader agenda of more stringent gun control measures, which NRA opposes.

The ad makes no mention of gun control, but McCain and Sen. Joseph Lieberman, D-Conn., are planning to introduce legislation later this month designed to close a loophole that allows weapons to be purchased at gun shows without a background check. Sen. Jack Reed, D-R.I., has already introduced similar legislation.