A hunter was arrested after allegedly shooting dead a 20-year-old Afghan refugee who had illegally entered Serbia from Albania, police said.

Security forces were patrolling the town of Pirot, in the south-east of the country, when they encountered a group of six refugees, one of whom had been shot in the chest, the defence ministry in Belgrade said.

They are believed to have illegally entered the country from Bulgaria.

Police arrested a man who was part of a group of four hunters on suspicion of shooting the refugee. "Upon the arrival of emergency services, doctors could only establish the death of a 20-year-old male citizen of Afghanistan," the statement added, reported AFP.

Millions of refugees and migrants travelled through the Balkans, many on their way to more prosperous northern European countries, in 2015.

In March, the so-called 'Balkan route' was declared closed after a razor wire fence was built to seal the Greek-Macedonian border. However Serbian authorities have been accused of turning a blind eye and allowing thousands of refugees to pass through the country.

According to Serbian authorities around 3,700 refugees have attempted to enter the country illegally since police began co-ordinated border operations with the military in July.