Lenient rules on buying guns in Florida and firearms transportation are subverting Puerto Rico's stricter gun laws and fueling a black market for weapons on the island, authorities say.

About 60 percent of the guns seized in Puerto Rico in the past decade came from Florida, according to estimates from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. Puerto Rican police linked illegal guns to many of the island's more than 7,000 murders in the last 10 years.

Officials say guns frequently are bought legally on the mainland and flown to Puerto Rico in airline luggage.

"They usually have been pre-ordered," said Marcial Orlando Felix, an ATF agent stationed in Puerto Rico. "There's a buyer awaiting them."

Authorities complain that airline regulations make it tougher to transport a dog to Puerto Rico than a suitcase full of guns and ammunition. Dogs require paperwork, fees and certification but gun owners generally need only to tell airlines the unloaded guns are packed in a secure container in checked baggage.

Felix and Puerto Rican Police Superintendent Pedro Toledo are lobbying for rules requiring airlines to notify them of passengers taking guns into Puerto Rico.

On March 5, authorities arrested two airline workers in Orlando on charges they attempted to smuggle guns to Puerto Rico. Orlando is a hub for about 3,400 of the 5,000 flights from Florida to Puerto Rico each year.

"What usually happens is, someone travels from Puerto Rico to Florida to buy guns at a gun show ... They go to Orlando because they have buddies there that can put them up and it is a short, inexpensive flight," Felix said. "That person makes a couple of trips and realizes this is easy. So he recruits two or three of his buddies in Orlando to do the same."