Several European countries have re-established border controls in response to an influx of refugees, after two decades of frontier-free travel across the continent.

On Tuesday, Hungary closed its informal crossing point into the European Union (EU), after it introduced laws that make “illegal border-crossings” a crime punishable by up to three years in prison.

Under the laws passed through Hungary’s parliament on September 4, damaging the barrier will also result in a five-year jail sentence, while obstructing the barrier’s construction is punishable by one year in prison.

The government in Budapest says it aims to halt the flow of the refugees into the country.

Meanwhile, Hungarian police say they have already detained 9,380 refugees crossing into the country from Serbia. On Monday, 7,437 asylum-seekers had entered the country, in comparison with 5,809 arrivals during the previous day.

Austria has also announced that it would dispatch its military to assist police forces in carrying out checks at its border with Hungary in a move aimed at stemming the wave of asylum seekers into the country.

Slovakia and the Netherlands also said they were imposing border checks in order to cope with the influx of the refugees.

Earlier this week, Germany decided to re-establish its border control process following complaints by German authorities in the Bavarian state capital, Munich. Berlin urged neighboring countries to follow suit.

Potential violations of international law

The United Nations (UN)’s refugee agency says that criminalizing people for crossing borders could be in violation of the 1951 Refugee Convention.

Europe is facing an unprecedented refugee crisis, which has escalated in recent months. The continent is now divided over how to deal with the flood of people, mainly Syrians fleeing the foreign-backed war in their homeland.

Although EU ministers failed to agree on the relocation of 120,000 migrants in a Monday summit, a majority of the ministers support the plan introduced months ago in principle. A final deal is expected to be reached by October 8.

According to figures provided by the UN, some 300,000 people have fled the Middle East and North Africa for Europe this year.