FORT LAUDERDALE — Undocumented migrants from Russia and other former Soviet countries were smuggled Sunday into Key West, Fla., authorities said, raising concerns that the war in Ukraine is spurring refugees and others to seek dangerous new routes to the United States.

Alyson Crean, a spokeswoman for the Key West Police Department, said a boat chartered from Cuba docked at the south end of Duval Street, in the heart of the city’s tourist district, around 4 p.m. Sunday.

Crean said Key West police were called after about 15 of the migrants, whom she identified as being from Russia or other countries, walked into Southernmost Beach Cafe. Police alerted the Department of Homeland Security and its sub-agency, U.S. Customs and Border Protection, about the landfall.

“They docked on a pier there and disembarked and went into the cafe,” said Crean, who referred additional questions to federal investigators.

The Department of Homeland Security confirmed Monday afternoon that 15 migrants from Russia and a pair of former Soviet republics were smuggled into the Keys on a sport-fishing vessel and taken into U.S. Border Patrol custody. Nine are from Russia, four are from Kazakhstan and two are from Kyrgyzstan, officials said, and all are being processed for deportation.

DHS said the incident was an example of "maritime smuggling.”

“Smugglers have no regard for the lives of migrants, and far too many lives are lost at sea as individuals take the dangerous journey in makeshift boats, rafts, and other vessels ill-equipped to handle the rough waters," DHS spokesman Eduardo Maia Silva said in a statement.

Anyone "attempting to enter the United States by sea, without a lawful basis to enter, will be subject to removal,” he said.

Officials in Monroe County, which includes Key West and the rest of the Florida Keys, said witnesses told them that the 15 migrants who showed up at the cafe may have been part of a larger group of about 40 individuals who traveled in the boat from Cuba. DHS did not respond to questions about whether officials are searching for any other passengers or crew, and what happened to the boat.

The other occupants, most believed to have been from Russia, departed before CBP agents arrived at the scene, county leaders said. Although Monroe County officials are accustomed to Cuban migrants landing in the Florida Keys, they said it was the first time they’ve encountered migrants from Russia or Eastern Europe crossing the Straits of Florida into the United States.

“This is something different and new,” said Monroe County Mayor David Rice, adding that officials initially treated the landing as a “national security event.”

“All we ever do when we have migrants land of any nationality is to make sure they are safe, but these people were not like the usual migrants,” Rice said. “They were well-dressed, on a chartered boat, and hadn’t been adrift for a week.”

Monroe County Sheriff Rick Ramsay said the migrants, many carrying luggage, arrived on a 30-foot vessel. He said there remains “some questions” about how many, if any, of the occupants “dissipated into the community” before they could be apprehended.

Ramsay cautioned it was premature to view this incident as a possible broader trend in migration patterns. Local authorities did not know if the group had recently fled the war or had been in Cuba for some time.

“Anything is possible, but we need more data, intelligence or landings to show this is something unusual versus an anomaly,” said Ramsay, adding that he thinks most of the migrants were from Russia and did not believe there was an ongoing threat to the public.

Shannon Weiner, director of emergency management for Monroe County, said the FBI is also assisting CBP and the Department of Homeland Security in investigating the incident. The FBI referred questions to DHS.

Lt. Cmdr Jason Neiman, a spokesman for the U.S. Coast Guard, said the Coast Guard is “aware of the incident and assisting” other federal agencies. Neiman said he is not aware of the Coast Guard interdicting other migrant vessels at sea that include refugees or migrants from Russia or Ukraine.

Nestor J. Yglesias, a spokesman for Homeland Security Investigations, an investigative arm of DHS, said in a statement that the agency is “looking into the matter” but declined further comment about an “ongoing investigation.”

Ukrainian war refugees and their families in the United States are growing increasingly frustrated with efforts to bring their relatives into this country.

On Saturday, The Washington Post reported that hundreds of refugees from Ukraine were gathered at the U.S. border in Tijuana, Mexico, joining refugees from around the globe.

Last month, President Biden said the United States would accept as many as 100,000 Ukrainian refugees, but the administration has yet to establish a way for them to arrive into the country directly.

Since Russia invaded Ukraine more than a month ago, more than 4 million residents have fled Ukraine.

Tens of thousands of Russians are also believed to have fled that country to escape economic sanctions and Russian President Vladimir Putin’s crackdown on domestic dissent against the war.

Russian citizens have also been stranded in countries around the world after airlines canceled flights to and from Russia.

Traditionally, the process for admitting migrants and refugees into the United States requires multiple security screenings that can take months or years to complete.

Before Biden’s announcement last month, fewer than 700 Ukrainians and eight Russians had been admitted as refugees from Oct. 1 to Feb. 28, State Department records show. The State Department did not immediately respond to requests for updated data since Biden’s announcement.

Customs and Border Protection has encountered more Ukrainian and Russian nationals at air, land and sea ports and borders this fiscal year, including in Florida, where their numbers rose from 92 in October to 434 in February.

CBP encountered more than 19,000 people from both countries since the fiscal year began Oct. 1, the majority from Russia, close to last year’s total of more than 22,600. Most requested admission at ports of entry, CBP records show.

Many Ukrainians have been admitted on a temporary status known as humanitarian parole, according to the Department of Homeland Security.

The Biden administration has been warning migrants from countries such as Cuba and Haiti for months to avoid risking drowning by making the hazardous journey by sea, which is far less common than attempting to cross at land borders in Mexico.

Homeland Security Secretary Alejandro Mayorkas said in July after social unrest in Cuba that “the time is never right to attempt migration by sea.”

“Allow me to be clear, if you take to the sea, you will not come to the United States,” Mayorkas said then, days after nine Cubans disappeared at sea after their boat capsized approximately 26 miles southeast of Key West.