LAS VEGAS — The first television advertisement attempting to convince Nevada voters to cast ballots in favor of stricter gun-purchase checks has hit the airwaves, and opponents of the initiative quickly responded by criticizing it.

The ad sponsored by the group Nevadans for Background Checks debuted Tuesday, featuring the president of the Nevada Association of Public Safety Officers claiming approval of Question 1 on the November ballot would reduce gun violence and save the lives of police officers.

Jim Dunlap, who heads the AFL-CIO affiliated association representing about 1,500 Nevada law enforcement officers, said it would be harder for criminals to get guns if voters pass the initiative.

The National Rifle Association responded with an emailed statement labeling as “simplistic” the claim that fewer police officers would be shot if background checks by licensed gun dealers were required when most firearms change hands.

Gov. Brian Sandoval, a Republican, and most Nevada sheriffs oppose the initiative.

Supporters say they have endorsements from other law enforcement officials, churches and business leaders.

The NRA also criticized funding for the Nevada initiative from former New York City Mayor Michael Bloomberg.

Campaign finance reports show that Everytown for Gun Safety Action Fund, a group affiliated with Bloomberg, contributed more than half the more than $800,000 that initiative supporters spent as of May.

NRA Nevadans for Freedom, a political action committee opposing the measure, reported nearly $140,000 in contributions for the same period. All was from the National Rifle Association.