Six people were injured in a knife attack at a demonstration in Antwerp, Belgium, on Thursday evening, police said. Two victims are in critical condition in hospital, according to police spokesperson Wouter Bruyns. The incident happened near the Operaplein (Opera Square) in the port city. Police caught two suspects who had mixed with the crowd at the protest. Four people were found stabbed inside the square, while two others were hurt nearby around Rooseveltplaats and Sint-Elisabethstraat. Authorities are treating the case as attempted murder, not terrorism, and are checking CCTV footage to ensure no other attackers are at large. About 50 people attended the protest outside the Opera House. The demonstration showed flags of the Kurdish Workers’ Party (PKK) and national flags, supporting Kurds in northern Syria fighting a government advance. According to the newspaper Het Laatste Nieuws, the protest was peaceful at first. Orhan Kilic, a spokesperson for Navbel, representing the Kurdish diaspora in Belgium, said families, women, youth, and children were part of the protest. He said, "Just as the protest was disbanding, the Kurdish demonstrators were attacked by a group of men. These men had sneaked into the demonstration and suddenly pulled out knives and began stabbing people indiscriminately. It is clear that this attack is not an isolated instance of senseless violence, but a motivated attack on a community." Forensic officers were seen at the square, and police have asked the public to avoid the area.