TEGUCIGALPA Honduran authorities said on Wednesday they had intercepted six Syrian nationals traveling on doctored Greek passports in the past week, including five who had been trying to reach the United States.
Police said there were no signs of any links to last week's deadly attacks in Paris that killed 129 people. Islamic State claimed responsibility for the shooting and suicide bombing assault.
Five of the men were detained late on Tuesday in the Honduran capital, Tegucigalpa, on arrival from Costa Rica, and had been planning to head to the border with neighboring Guatemala, police said. They said passports had been doctored to replace the photographs with those of the Syrians.
Anibal Baca, a Honduras police spokesman, said the five were trying to reach the United States.
A sixth man was turned away on Friday on arrival by plane from El Salvador, and was sent back. They are the first such cases of attempted illegal entry by Syrians into Honduras since the Central American country started compiling records in 2010.
However, the case appears to form part of a spate of such incidents. Police in the former Dutch Caribbean colony of St Maarten on Saturday arrested three men they believed to be Syrians who arrived on a flight from Haiti and were traveling on false Greek passports.
In Paraguay, police detained a Syrian man on Sunday who was traveling on a stolen Greek passport.
Reports that at least one of the Paris attackers may have slipped into Europe among migrants registered in Greece prompted several Western countries to begin to question their willingness to take in refugees from war-torn Syria.
Republican Senator James Risch of Idaho said he found the news "very troubling", and wondered whether the men formed part of a militant sleeper cell to be planted in the United States, or whether it was something far more innocent.
"It is very, very suspicious and I can tell you that the intelligence community is drilling down on these five right now," Risch told CNN, adding that U.S. intelligence does not know the Syrians' motive.
"So far they have not used the southern path to enter our very porous southern border. They haven't done that in the past. This was clearly an attempt to do this by five Syrians, and what they had in mind after they got here, that remains to be seen," said Risch, a member of the Select Committee on Intelligence.
Seizing on concerns about an influx of migrants from Mexico and Central America across the U.S. southern border, U.S. Republican presidential front-runner Donald Trump has vowed to force Mexico to pay for the United States to construct a wall between the neighbors.
Even before the Paris attacks, Trump had vowed to send all Syrian refugees accepted by the United States back to Syria if he is elected.
Since 2014, countries in South America, mainly Brazil and Argentina, have witnessed a notable increase in asylum-seekers in the region, particularly Syrians, the UN refugee agency says. But it is still rare for refugees from Syria and other Middle Eastern countries to seek asylum after crossing the United States' southern border.
In Washington, Republicans are resisting President Barack Obama's plan to admit 10,000 Syrian refugees in the coming year.
"We received information from (fellow) police services that these five Syrians left Greece and passed through Turkey, Brazil, Argentina and San Jose in Costa Rica before finally reaching Tegucigalpa," Baca said.
"They are normal Syrians," the police spokesman added, saying there was nothing to indicate they were tied to the Paris attacks.
Television footage showed the men dressed in casual clothing and grinning as police officers escorted them at the airport. They were then piled into the back of a police pick-up truck, flanked by officers with pistols on their hips.
Honduran newspaper La Prensa said the five men detained on Tuesday were aged 23 to 33.
"Greek diplomats arrived in the terminal area and confirmed the men didn't speak a word of Greek," the paper said.
The Honduran government said it had involved Interpol in the investigation. Use of false passports is increasingly commonplace among Syrian refugees who often find themselves in other countries, having left their own documents behind in their rush to flee.
(The story has been refiled to correct second paragraph to show IS claimed responsibility for the attacks)
(Additional reporting by Frank Jack Daniel and David Alire Garcia in Mexico and Eric Beech in Washington; Writing by Simon Gardner; Editing by Peter Cooney and Ken Wills)