Four suspected members or sympathizers of the Islamic State (ISIS) group have been detained in Germany and Switzerland in a cross-border operation, prosecutors from the two countries said Tuesday, according to the AFP news agency.
In Switzerland, three people were picked up in the cantons of Zurich, Sankt Gallen and Lucerne, national authorities said, adding that seven further searches were also carried out.
The suspects, whose identities were not released, are accused of "participation in or support for the outlawed organization Islamic State".
In Germany, a man was detained in the western town of Roemerberg, federal prosecutors said.
Identified only as Aleem N., he is "strongly suspected of preparing a serious violent attack threatening the security of the state and of belonging to a foreign terrorist organization".
He is believed to have attempted to travel from Germany via Turkey to Syria in September 2020, according to AFP.
German intelligence services estimate that more than 1,150 people have travelled from Germany to Iraq and Syria since 2011 for Islamist reasons.
More than a third have since returned to Germany, while at least 270 have been killed in Iraq or Syria.
Germany has been hit by several terrorist attacks in recent years.
The worst such attack took place in December of 2016, when Tunisian terrorist Anis Amri killed 12 people and injured dozens more when he drove a truck into a Christmas market in Berlin.
While Switzerland has not been targeted by terrorism as other countries in Europe have been in recent years, the country in 2017 arrested suspected radicals who plotted attacks in France.