IDOMENI, Greece (AP) — Police clashed Friday with thousands of migrants stuck at the border between Greece and Macedonia, waiting to continue long journeys into European Union countries where they hope to seek asylum.

Greece has seen a huge wave of migrants, 160,000 so far this year, many fleeing war and persecution in Syria and Afghanistan. Most take rubber boats from Turkey to the Greek islands, then make their way north.

About 39,000 people, mostly Syrian refugees, have registered as passing through Macedonia in the past month, twice as many as the month before. They previously encountered little resistance at the border, but the recent influx has overwhelmed Macedonian authorities who this week declared a state of emergency and stopped many from crossing.

On Friday, police fired stun grenades into a crowd of 3,000 migrants that made several attempts to charge them. At least eight people were injured.

Here is a gallery of images by Associated Press Photographer Darko Vojinovic showing the chaos at the border.