Belgian prosecutors say three houses have been searched and two people arrested in connection with an ongoing investigation into the activities of a suspected terrorist group.

Ester Natus, a spokeswoman for the Federal Prosecutor's Office, said Friday's developments were not connected to the attacks claimed by the Islamic State group in Brussels and Paris that killed a total of 162 people over the last year.

Natus provided no details about the activities in which the suspects allegedly engaged or were planning.

The prosecutor's office said in a statement that the searched houses are located in the Schaarbeek and Haren neighborhoods of Brussels, and in the eastern city of Liege,

Natus says a judge is expected to decide on Saturday whether the two people arrested should be kept in custody.