Greek authorities say six people were injured and four others were arrested following an overnight fight in a refugee camp near the northern Greek city of Thessaloniki.

Police said Monday the three-hour fight in the Lagadikia camp involved about 250 people and apparently broke out after a group of Syrians said a group of Algerians had harassed Syrian women. The fight quickly spread through the camp, with those involved using knives and planks of wood.

An increase of arrivals of refugees and other migrants across Greece's northeastern border with Turkey has led to overcrowding in camps in northern Greece, with Lagadikia now housing 250 people more than its 360-person capacity. The new arrivals are being housed in offices and other communal areas of the camp, and sleep on the floor.