PARIS (AP) — Police reinforcements are arriving in the French port city of Calais after clashes among migrants left 22 people injured, as the interior minister warned of a worrying spike in violence.

Interior Minister Gerard Collomb told reporters in Calais on Friday that five of the victims were injured by gunfire in Thursday's fighting, blaming "totally organized" gangs. Police are seeking a shooting suspect but have made no arrests.

Collomb said two extra police units were en route and warned of growing tensions in Calais, where migrants converge in hopes of crossing to Britain.

Authorities said that Afghan and Eritrean migrants had been fighting with sticks and stones after a meal distribution before the shots were fired. Firearms are rare among migrants.

The government closed a vast Calais migrant camp in 2016.