SARAJEVO, Bosnia-Herzegovina — The United Nations mission in Bosnia called Monday for urgent action to stop violent pushbacks and collective expulsions of refugees, asylum-seekers and migrants along the Croatian border following an incident last week involving 50 “visibly exhausted” men.

The mission said in a statement that U.N. teams and representatives of non-governmental organizations encountered the group walking near a border crossing with Croatia on Friday with wounds on their bodies and in need of clothes.

The men said they had their cellphones, money and belongings taken away when they tried to cross the border and that they were beaten with sticks back into Bosnia, according to the statement. Health workers from the NGOs provided “urgent medical assistance” to half of the men, the statement said.

There was no immediate response to the report from Bosnia or Croatia. Croatian authorities have repeatedly denied in the past using physical force against migrants trying to reach the European Union member nation from Bosnia.

Collectively removing people from a country without individual consideration of their circumstances is illegal under a European human rights treaty.

Thousands of migrants have been stuck in Bosnia while trying to reach Western Europe. Many have complained of unlawful pushbacks and violence by Croatian border forces.

The U.N. mission in Bosnia noted that “pushbacks and collective expulsions are prohibited under international and EU law.”

“We urge the concerned states to investigate the incident that took place on the 2nd of April and for all perpetrators to be appropriately sanctioned,” the mission said.