As a hostage siege in a Sydney cafe captures the world's attention, another hostage siege has ended in Belgium.

Armed police in the western city of Ghent stormed an apartment on Monday where a gunman had taken one person hostage.

The state prosecutor's office says the victim was safe and three other men were detained.

Belgian TV cited neighbors as saying the apartment had been used by drug dealers.

Authorities don't think the case is linked to Islamic extremism.

The hostage siege was happening as an Iranian refugee in Sydney took about 20 people hostage at a popular cafe, in what authorities were treating as a terrorist event.