Three Syrian men who entered Germany as migrants were arrested today on suspicion of being connected to ISIS. The Guardian reports the men had been under surveillance for months:

Three Syrian men arrested at refugee shelters in Germany on Tuesday were suspected Islamic State members who appear to have been brought into the country by the same network that smuggled militants into France to carry out deadly attacks last November, German authorities have said…

The suspects – identified as Syrian asylum seekers – had been under surveillance for several months following a tipoff received by Germany’s domestic intelligence unit, the BKA, a spokesman for the federal prosecutor in Karlsruhe said.

The NY Times has more on the connection between the men arrested Tuesday and the Paris attackers:

Thomas de Maizière, the German interior minister, said that the travel documents the men were carrying when they were arrested on Tuesday had been issued by the same authority as ones found on some of the men who carried out the attacks in and around Paris in November. The authorities also said that the three Syrians appeared to have used the same smugglers to enter Germany and to apply for asylum as some of those involved in the terrorist assaults in France.

“It could be that this was a sleeper cell,” Mr. de Maizière told reporters.

Prosecutors said in a statement that they believed the three came to Germany in November to carry out a planned attack for the group, also known as ISIL or ISIS, or to await instructions for one.

So far authorities are saying there is no indication they had a specific target in mind.

There have been two attacks linked to ISIS in Germany already this year. An axe attack on a train and a suicide bomb attack outside a concert. The concert bombing injured 15 people but only killed the 27-year-old bomber. That attack might have been more deadly but the bomber was denied entrance to the concert.