Dutch police today detained several people in Amsterdam who defied a ban on protests, imposed after violent incidents that occurred on the sidelines of a football match, and raised white banners in front of the city hall, according to a Reuters eyewitness.

Dutch news agency ANP reported that six people were taken into custody. A police spokesman was unable to immediately confirm that number.

The atmosphere remains tense in the city after violence erupted before and after last week’s football match between Israeli side Maccabi and Ajax Amsterdam. At least five people were injured in those incidents, which Dutch authorities as well as foreign leaders, including Israeli Prime Minister Benjamin Netanyahu, have denounced as anti-Semitic.

Following the violence, local authorities imposed a ban on the protests until Thursday morning.