The federal prosecutor's office said the fifth suspect was apprehended in Brussels Tuesday.
The three others were detained after a major anti-terror raid last week. They include a suspect who escaped alive from a firefight with police in eastern Verviers when two others were killed. Authorities claim they were part of a group only hours away from a major terror attack.
Another person suspected of being linked with jihadi terrorists in Belgium was detained Sunday in Athens, Greece.
The prosecutor said Wednesday the two people killed in Verviers were Belgian nationals in their twenties.
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