The Islamic State claimed responsibility for the August 6 terrorist attack in the Belgian city Charleroi, in which a man with a machete slashed two police officers while screaming "Allahu Akbar."
One of the officers was seriously injured. The terrorist was shot dead at the scene by a third officer.
The Belgian government stepped up security at police stations following the attack.
Meanwhile, police in the eastern Belgian city Liege arrested another man with a machete a day later. It is not known why he had the machete and he did not attack anyone.
The Islamic State called on its followers to carry out terrorist attacks against mainland Europe and America, which do not require in-depth planning or extensive coordination .
Other European jihadists heeded the call to travel to Syria.
Two boys from Bradford in the UK posted pictures of themselves online with an AK-47 and pledged allegiance to the Islamic State's Caliph Abu Bakr Al-Baghdadi. Junaid Iqbal, 16, and Ibrahim Iqbal, 15, posted the pictures to Ibrahim's Facebook page.
Their mother left her husband and took her five children, then aged 15, 14, 8, 5 and 3, to Syria last year.
A 2014 video shows fighters pledging to ISIS and vowing to conquer Europe.