A police spokesperson said a 29-year-old man was detained on Sunday after behaving aggressively in a café. He later died in hospital.
An investigation has been launched in Belgium after an Algerian man died in hospital, hours after being arrested by Antwerp police.
A 29-year-old man was arrested at midday on Sunday after behaving aggressively in a café, according to Antwerp police spokesman Sven Lommaert.
According to the spokesman, he was "trying to hit people, was very agitated" and when officers arrived on the scene, they found he had a head injury and appeared to be "under the influence" of drugs.
Police subdued the man on the ground, using handcuffs, and called the emergency services. When medical personnel arrived 12 minutes later, the man was unresponsive, the spokesman said.
Ambulance workers resuscitated him and took him to hospital, where he died between 21:00 and 22:00.
The public prosecutor's office said it had opened a judicial investigation into "the exact circumstances of the arrest and death" of the suspect.
Footage posted on social media claims to show the man lying on the ground and being held by two police officers during an arrest. Euronews is working to try and verify it.
Antwerp Police said on Twitter they would refrain from commenting further on the case.