BUDAPEST Three months after throngs of migrants turned the Keleti station in Budapest into a squalid symbol of Europe's disarray, the grand 19th-century rail terminus has taken on a no less divisive role in a mounting debate over links between terrorism and the chaotic influx of people fleeing war and poverty in the Muslim world.
The Hungarian government, widely criticized in the West for its hostility toward refugees, has seized on evidence of visits to Budapest in September by Salah Abdeslam, whom the authorities have identified as the only known survivor among the terrorists in the Nov. 13 Paris attacks, to assert that the migrants who camped out at the Keleti station provided a pool of willing terrorist recruits.
That claim, however, has been derided by investigators in Belgium looking into the movements of Mr. Abdeslam, a Brussels resident who is still at large. Eric Van der Sijpt, a magistrate with the federal prosecutor's office in Brussels, dismissed the Hungarian account of Mr. Abdeslam's signing up refugees as accomplices as a "political statement" that defied known facts and logic.
Noting that a terrorist recruiter would "have been lynched in five minutes" by asylum seekers who had fled Syria to get away from groups like the Islamic State, he said there was no evidence that migrants in Budapest had been recruited as terrorists. Far more plausible, he said, was that the flow of migrants had provided cover for two unidentified men who were picked up by Mr. Abdeslam in Budapest in September and who have since been linked to the Paris attacks.
But whether providing terrorist recruits or merely cover for existing militants, said Peter Szijjarto, Hungary's foreign minister, Europe's migrant crisis has "opened many opportunities for terrorists."
The Hungarian connection to the Paris attacks suggests that as many as four people with links to those who carried out the carnage might have entered Europe along the migrant trail.
They include two of the suicide bombers who blew themselves up outside the Stade de France and appear to have entered Europe through Greece using Syrian passports. The fake Belgian identity cards used by the men picked up in Budapest by Mr. Abdeslam in September continued to be used after Nov. 13, including for a money transfer from Belgium to a French associate of the suspected ringleader of the Paris plot. This has led to suspicions that the two men collected in Hungary remain alive, though no one knows their real identities or what role, if any, they played in the attacks.
In a separate case, the authorities in Finland arrested two recently arrived Iraqis last week on suspicion of having participated in a massacre carried out by the Islamic State in Iraq. Finland's interior minister, Petteri Orpo, said in Helsinki on Thursday that around 300 asylum seekers in the country had some links to terrorism.
This commingling of terrorism and migration has amplified not only security concerns but also public doubts over whether the European Union, which has often played down such risks and accused Hungary of being alarmist, has a grip on the problem.
Even after the Paris attacks, the European bloc's counterterrorism coordinator, Gilles de Kerchove, said at a news conference in Brussels that the link between terrorism and migrant flows was "nonexistent."
But what should have been a public relations victory for Hungary after the disclosure of Mr. Abdeslam's visit to Budapest to collect the two men has turned into yet another opportunity for critics of Hungary's hard-line anti-migrant prime minister, Viktor Orban, to accuse his government of playing loose with facts to score political points.
Zsolt Molnar, the chairman of the Hungarian Parliament's national security committee and an opponent of the government, said there was clear evidence that Mr. Abdeslam had met at Keleti with the two men now suspected of involvement in the Paris slaughter. But, he added, there was nothing to indicate that the men were migrants who, after their arrival in Budapest, decided to join the terrorist plot.
Citing confidential intelligence information that he said he could not elaborate on, Mr. Molnar said it "was a fact that they were at the Keleti station, but the rest is just a political communication."
Julia Ivan, a lawyer with the Hungarian Helsinki Committee, a group that provides legal aid to refugees, said the government's account of what happened at Keleti fit into a pattern of distortion and exaggeration that "is not about managing real problems but all about winning votes" by convincing Hungarians that they need Mr. Orban to protect them.
A new government website dedicated to denouncing a European Union plan to spread asylum seekers around the Continent under a quota system bristles with dark warnings of terrorist hordes ready to pounce on Hungary.
"No one can say how many terrorists have arrived so far, and many people continue to arrive each day," it warns. "Even one terrorist would be too many."
In November, Hungary's anti-terrorist police announced that they had thwarted a plot involving an "international dimension" and a bomb-making laboratory. The case quickly collapsed when the terrorism suspects turned out to be Hungarian and Slovak hobbyists who collected World War II memorabilia.
Mr. Orban has been warning since the start of the year that Muslim migrants could well turn out to be terrorists. Early this month, his chief of staff, Janos Lazar, jumped on reports from Belgium of Mr. Abdeslam's visits to Hungary as proof of a link between refugees and the carnage in Paris.
Describing Mr. Abdeslam as "one of the chief organizers of the Paris terror attacks," Mr. Lazar said the Brussels resident had spent time at the Keleti station and "recruited a team" of terrorists among unregistered migrants. Hungarian media close to the government trumpeted this as a vindication of Mr. Orban's warnings, which his fellow European leaders have mostly scorned.
Magyar Idok, a conservative pro-government newspaper, said the "relationship between migration and terrorism" showed how "problematic and dangerous" it was to allow hundreds of thousands of people from the Middle East and elsewhere to roam unchecked.
At a news conference in Budapest last Thursday, however, Mr. Lazar seemed to back away from his previous account. He said only that Mr. Abdeslam had been at Keleti and had met there with people whom, according to the Belgian prosecutor, Mr. Abdeslam later drove out of Hungary in a rented Mercedes-Benz.
Mr. Lazar said this was based on information from intelligence services in Hungary and abroad. He declined to give details.
Katalin Simon, a Hungarian woman who spent much of the summer at the station working with migrants, dismissed Mr. Lazar's initial account as "ridiculous" and questioned whether he had any real information or was merely pushing the government's anti-migrant agenda.
"There is almost zero chance that somebody who is running away from terrorism would suddenly decide at Keleti station that they want to become a terrorist," she said.
Ossamah Bourgla, a Syrian-born doctor who has lived in Hungary for 34 years and who helped at the station over the summer, said it was "possible that the Paris terrorists used the chaos at Keleti to meet there and get through unseen." But he added that any attempt to recruit for a terrorist operation would have been immediately known.
"If there had been any recruitment there, the refugees would have reported it to us," he said. "It was in their interest."
Zoltan Kovacs, a Hungarian government spokesman, declined to comment on what evidence there was of terrorist recruitment at Keleti. He said that only 176,954 of the around 390,000 migrants who had entered Hungary this year had officially registered and that "this means more than 200,000 people are floating around who are potentially terrorists."
Helene Bienvenu contributed reporting.