A gunman opened fire Saturday outside a Turkish cafe in the Belgian city of Antwerp, killing one person and injuring at least two others.

Two people, believed to be a father and his son, were arrested and a gun was seized, the Daily Mail reported.

The motive was not immediately known, but there’s been tension between the Turkish and Kurdish residents of the neighborhood, the newspaper said.

Local reports said two of the shooting victims had been targeted; the other victim a bystander.

Last May, two female police officers were stabbed in their backs in another Belgian city, Liege, by an attacker who then stole their weapons and fatally shot them. A bystander was also killed.

Authorities called it a terrorist attack. The gunman, identified as Benjamin Herman, had been arrested for drug offenses and released the day before. Police speculated he was radicalized while in jail.

In March 2016, suicide attacks on a Metro station and the Brussels Airport by ISIS killed 32 people.