Three Syrian men suspected of being sent to Germany by ISIS were arrested Tuesday, officials said.
The trio were detained in a massive police operation in the northern German state of Schleswig-Holstein. They appeared to have overlapping relationships with terrorists who laid siege to Paris in November, according to authorities.
Federal prosecutors said more than 200 officers participated in the raids, which netted suspects identified only as 17-year-old Mahir Al-H., 26-year-old Mohamed A. and 18-year-old Ibrahim M.
"The three men are suspected of coming to Germany in November 2015 in order to either fulfill an already received mission or to be ready for further instructions," prosecutors said in a statement.
It said domestic intelligence showed Mahi Al-H. had been trained and briefed on "the use of weapons and explosions" after he joined ISIS in the Syrian city of Raqqa, sometime before September 2015.
The suspect then committed — along with Mohamed A. and Ibrahim M. — to travel to Europe with the purpose of carrying out missions, the statement added.
It said the men were given passports, U.S. dollars and cellphones with "pre-installed communication programs" by ISIS before they left Syria and traveled to Germany — by way of Turkey and Greece — in mid-November.
Germany's Interior Minister Thomas Maiziere said it did not appear that the men had "concrete" plans for any attacks, telling reporters they may have been a "sleeper cell" awaiting instructions.
The trio used the same smuggling network as the Paris attackers to get to Europe and may have gotten fake passports from the same workshop, Maieire told a press conference.
Germany took in more than 2.1 million immigrants last year — many from war-torn Syria. Along with the influx has come fears that potential ISIS operatives may have disguised themselves as refugees.
Officials have been grappling with how best to confront the threat of ISIS terror in wake of a series of violent attacks this summer — including two involving migrants.
A July 18 ax-and-knife attack by an ISIS-inspired Afghan asylum-seeker aboard a train near Wuerzburg left five people seriously injured.
Six days later, a Syrian failed asylum-seeker blew himself up outside a popular music festival in the southern city of Ansbach, wounding dozens. Authorities later said he had pledged allegiance to ISIS in a video.