Danish police said they had arrested four people on Thursday at different addresses near Copenhagen on suspicion of having been recruited by the militant group Islamic State (IS) in Syria to commit terrorist violence.

Ammunitions and weapons were found in a connected search, the police said.

“All four suspects are accused of having violated the penal code … by allowing themselves to be recruited by IS in Syria to commit terrorists acts,” a statement by Copenhagen police said.

Neighboring Sweden on Thursday charged a 20-year-old man with terrorism for allegedly building a suicide bomb with the intent of staging an attack in Sweden.