North America’s top professional sports leagues have issued warnings to their players about a growing threat from high-tech, organized burglary rings, whose tools of choice are passports, cutting-edge technology and a 90-day calendar.

The NBA memo, citing FBI intelligence, specifically linked the crimes to “transnational South American Theft Groups” that target “professional athletes and other high-net-worth individuals.” These groups are known for using “advanced techniques” such as pre-surveillance, drones, signal-jamming devices and other cutting-edge technology. The NFL highlighted the risks posed by what it called “organized and skilled groups” of burglars targeting wealthy athletes.

While the warnings did not name victims, they were issued after the homes of athletes including Kansas City Chiefs stars Patrick Mahomes and Travis Kelce and Milwaukee Bucks forward Bobby Portis were recently burglarized. The tactics described in the memos bear a striking resemblance to a wave of break-ins targeting affluent residents in Southern California.

Federal and local officials from Los Angeles and Orange County have reported a spike in break-ins by what they call “burglary tourists” — criminals from Central and South America who legally enter the U.S. on 90-day tourist visas under the Electronic System for Travel Authorization (ESTA). But instead of packing swimsuits and sunscreen, police said these individuals are armed with disguises, video equipment, trail cameras and Wi-Fi jammers. They target wealthy neighborhoods and gated communities before moving on to avoid detection.

These “burglary tourists” have been at work for at least five years, but their operations have intensified in recent times as information about addresses and even pictures of properties have become increasingly accessible.

“Transnational gangs might not know everything about the house that they are breaking into,” LAPD Chief of Detectives Alan Hamilton told NBC News on Friday. “But there’s always a possibility these suspects know who they are and monitor the athletes’ social media and movements.”

Minnesota Timberwolves guard Mike Conley’s home was also burglarized in September while he was attending an NFL game, The Minnesota Star Tribune reported.

Portis posted on Instagram on Nov. 3 saying his “prized possessions” were stolen from his home during his team’s game the previous day.

Kelce’s and Mahomes’ homes in Kansas City were broken into hours apart in October. The burglars made off with $20,000 in cash and caused $1,000 in damage to Kelce’s home, according to a police report obtained by NBC affiliate KSHB of Kansas City.

Mahomes has called the ordeal “frustrating” and “disappointing.”

This trend has spread to other cities including Chicago, Houston and Dallas.

“Law enforcement has long recognized this pattern of crimes across the Midwest,” Hamilton said. “It’s not something they have been immune to.”

Law enforcement from coast to coast, including the FBI, has been tracking these criminal networks for years, with suspects linked to South American gangs appearing in nearly every state, Hamilton said.

“It’s totally military”-level technology, Orange County District Attorney Todd Spitzer told NBC News over the summer. “People we’ve arrested here in Orange County have criminal records coming from the country of Chile.”

If Southern California law enforcement has made progress in reducing these crimes, it may be driving more of these operations to other regions of the country.

The NBA and NFL urged players to take preventive measures, such as activating alarm systems and surveillance cameras, securing valuables in safes and avoid oversharing on social media.

“The FBI reported that, in most of the incidents, the homes were equipped with alarm systems that were not activated,” reads the NBA memo obtained by NBC News on Friday. “The FBI also reported that the homes were all unoccupied and, in most cases, no dogs were present.”