ZAGREB, Croatia (AP) — A Croatian hospital says a migrant is fighting for his life after being shot Friday by police.

Doctors in the Croatian port of Rijeka said Sunday the unidentified migrant suffered multiple bullet wounds to his chest.

Croatian police have said they fired shots at a group of migrants Friday “to protect Croatia’s borders.”

Police say they’ve sent a team to investigate the circumstances of the shooting, which took place at the Gorski Kotar mountains, about 30 kilometers (19 miles) from the border with Bosnia.

Rights groups have accused Croatian authorities of using excessive force against migrants illegally entering from Bosnia and Serbia. Croatia has repeatedly denied the charges.

Thousands of migrants from the Middle East, Africa and Asia have become stuck in the Balkans while trying to reach Western Europe.