BERLIN (AP) — Police say that two Kosovo-born brothers have been detained on suspicion that they were planning an attack on a shopping mall in western Germany.

Police said that the men, ages 28 and 31, were detained in Duisburg in the industrial Ruhr region in the early hours of Friday. Authorities suspect that they may have been planning an attack on the Centro mall in nearby Oberhausen.

They say authorities are probing how far along the suspected attack plan was and whether anyone else was involved.

Police say they increased their presence at Centro and a nearby Christmas market on Thursday evening after receiving a tip.