MIAMI — The gunman who killed five people at Fort Lauderdale-Hollywood International Airport exposed security vulnerabilities at airport public areas that were once an afterthought, experts say.

When National Guardsman Esteban Santiago allegedly killed five people and injured eight others after grabbing a gun from his luggage and loading it in a bathroom, his murderous rampage highlighted a point of weakness: areas outside of screening checkpoints such as baggage claims, check-in counters and passenger pickup zones where security is comparatively light.

"You're a sitting duck," said Peter Tarlow, a tourism and security expert based in Texas. "Nobody is checking anything."

Santiago flew to Fort Lauderdale with an unloaded handgun in his checked luggage, which he loaded in a baggage claim bathroom after landing. Then he walked out of the bathroom and shot 13 people, law enforcement sources said.

Federal rules allow airline passengers to "transport unloaded firearms in a locked hard-sided container as checked baggage only," according to the Transportation Security Administration.

Ammunition and firearm parts can also be carried separately in checked baggage.

It may be time to rethink those rules, Tarlow said.

"You can't have (more than) 3.4 ounces of shampoo, but we're allowing people to travel with guns?" he asked.

Airport security expert Kenneth J. Button, who teaches at George Mason University, said the luggage area of airports in the United States aren't generally considered a top priority for safety measures.

Drugs are more of a concern, Button said, particularly in South Florida, where it's not unusual to see trained police dogs sniffing for contraband.

"I think we need to review security more in the luggage areas of airports," he said. "But there is no absolute answer. Like accidents on the roads, you just try to reduce them."

U.S. Rep. Debbie Wasserman Schultz, a Florida Democrat whose district includes the airport, said she plans to ask TSA and Homeland Security leaders in Washington to address questions raised by the gunman's suspected actions, including the security of baggage claim areas and whether passengers should be able to check guns.

"You want to make sure you have the most security possible while leaving people with the most freedom of movement possible," she said.

Other countries with terrorism problems have started checking vehicles well before they arrive at airports, said Thomas Pasquarello, a former Drug Enforcement Administration special agent who worked at Miami International Airport and is now a private security consultant.

"(But) I can't see that happening in the U.S.," Pasquarello said. "The traffic issues would be too severe. . . . I'm not sure there's a way you can prevent this kind of incident if you value living in a free society."

Santiago seems to have broken no U.S. laws by flying with his firearm and ammunition in checked baggage.

But other passengers are stopped at security checkpoints trying to bring guns onto planes. TSA says it discovered 2,653 firearms in carry-on bags at checkpoints around the nation in 2015. That's an average of more than seven firearms per day.

The attack in Fort Lauderdale was much less sophisticated than the July attack at Istanbul's Ataturk Airport, where three suicide bombers detonated explosive vests at an international terminal and in a parking lot, while others shot unsuspecting travelers in the terminal. Forty-five people were killed.

Santiago simply departed his flight, got his luggage, took out his gun and loaded it in a bathroom, before walking to the luggage ramp and shooting 13 people, five of whom were killed.