A migrant pulls a child away from the edge of the platform at the train station in Nickelsdorf, Austria, September 11, 2015.

Hungarian Prime Minister Viktor Orban warned on Friday that his police would take tougher action from next week against a wave of migrants who he said had rebelled against authorities, seized railway stations and refused to be registered.

Hungary, a key transit country for migrants and refugees trying to reach richer and more generous European Union countries such as Germany and Sweden, is racing to construct a fence along its border with Serbia by early October to stem the flow.

More than 170,000 migrants have crossed into Hungary from Serbia so far this year. Most try to avoid being registered in Hungary for fear of being stranded there or returned there later on, encouraged by a temporary agreement by Germany and Austria to accept refugees.

“Considering that we are facing a rebellion by illegal migrants, police have done their job in a remarkable way, without using force,” Orban told reporters after a meeting with Manfred Weber, chairman of the conservative European People’s Party group in European Parliament.

“They have seized railway stations, refused to give fingerprints, failed to cooperate, and are unwilling to go to places where they would get food, water, accommodation and medical care … They have rebelled against Hungarian legal order.”

Orban said that, from Sept. 15, when tougher laws on immigration are due to take effect, migrants who cross Hungary’s border illegally will be arrested.

“From the 15th, Hungarian authorities cannot be forgiving of illegal border-crossing,” Orban said.

He also urged the EU to help Greece, the first EU landing point for the migrants, many of them refugees from conflicts in Syria, Iraq or Afghanistan who head on through Macedonia and Serbia to Hungary.

“There should be a quick decision to create a legal basis and deploy European forces to the border of Greece to enforce European law instead of the Greek authorities,” Orban said.

Hungary has accused Greece of shirking its responsibility under EU rules, as the first entry point into the bloc, to register and process asylum requests by migrants arriving by boat from Turkey.

Hungarian prisoners and soldiers are working to complete the massive fence, which is intended to seal Hungary off from Serbia.