Belgrade, SERBIA — Police and migrants clashed violently in Bulgaria’s largest refugee camp Thursday night, resulting in hundreds of arrests. In response, the country’s prime minister vowed Friday to move hundreds of refugees to closed camps and begin deporting others.

Around 400 residents of the camp, most of them from Afghanistan, were arrested for clashing with riot police Thursday. About 2,000 refugees were involved in the conflict, police said.

“You see there is no window left unbroken,” said Bulgarian Prime Minister Boiko Borisov, according to Reuters. “The people who committed these acts of vandalism will be brought to justice.”

“Based on an agreement between the European Union and Afghanistan we have asked for a plane to start extraditing people there in early December,” said Borisov. “As for the rest, all who have acted brutally and violated public order will be moved to closed camps.”

Video published on the news website Balkan Insight showed refugee youth hurling stones at the police and setting tires and wood ablaze, sending plumes of smoke skyward. Authorities used water cannons and rubber bullets to bring the riot under control. 24 police officers were injured, and some 60 soldiers were deployed to help quell the violence.

Camp volunteers claim that the police used excessive force and attacked refugees who had not participated in the riot, according to Balkan Insight, citing photographs of bruised and bloodied refugees.

The refugees allegedly rioted in anger at a temporary quarantine placed on the camp, which holds 3,000 people, after local media reported that contagious diseases were spreading there.

The head of the state refugee agency, Petya Parvanova, said Thursday there was no medical reason to quarantine the camp, but that local authorities had sealed it off after residents protested.

Residents of Harmanli have grown wary of the refugees after violent incidents in the camp – notably a brawl involving 800 migrants and the stabbing of two 19-year-old refugees in August.

“They are scared. It is a small, cozy town,” said Elena, a woman from the nearby city of Plovdiv who declined to give her last name, of her relatives in Harmanli. “Lately people have been living a more closed life, because you have these refugees in big groups of 10 or 15 people walking around — drinking alcohol and energy drinks and looking at the women.”

Anti-migrant sentiment has surged across Bulgaria over the past few years, as a vast influx of more than a million people — braving deadly sea journeys and crossing thousands of miles of terrain — sought refuge in Europe.

Vigilante groups kitted out in bullet-proof vests and battle fatigues patrol border zones, detaining refugees attempting to enter the country. Bulgarian nationalists have demanded the closure of the country’s camps.

Following a refugee deal with Turkey earlier this year, which has come under increasing strain, the flow of migrants into the EU dramatically decreased. Smuggling from Turkey’s western coast was vastly curtailed and police cracked down on illegal migration in Macedonia, Bulgaria, Hungary and Serbia.

Bulgarian border guards have also been forcing refugees back to Turkey, often with brutal violence. In one instance last year, two refugees froze to death after having their legs broken by border guards, prompting outrage from rights groups.

“The Bulgarian government should immediately put a stop to summary returns,” said Human Rights Watch in a report last year, “and hold those responsible to account.”

Refugees normally enter Bulgaria from neighboring Turkey, stealing across the border on foot despite a razor-wire fence that stretches across about half of the frontier. Around 17,000 migrants have reportedly been caught in Bulgaria this year, a significantly lower figure than last year.

Tighter border policing by both Bulgaria and Turkey has somewhat reduced the refugee flow. Serbia has additionally bolstered its military presence along its eastern border with Bulgaria.

Migrants, however, have sought alternative routes.

In September, two Iraqis — including a 6-year-old boy — drowned in the Danube River while attempting to smuggle by boat from northwestern Bulgaria into Romania. Romanian police recently broke up a smuggling ring, transporting Afghans and Iranians in the country’s northeast.

And this week, Croatian police caught a number of Iranian men who had illegally entered from Montenegro, in an attempt to bypass better-policed areas of the Balkans.