In the past few weeks, 777 foreign nationals, mainly from Serbia, Ukraine and Romania, who were convicted of trafficking humans, have been released by Hungary, according to the prison directorate’s response to Reuters inquiries on Wednesday.

The government of Prime Minister Viktor Orban, citing prison overcrowding, passed a decree in April that allowed foreign nationals who were found guilty of smuggling people to be freed, as long as they left Hungary within 72 hours of their release.

The decision sparked a backlash from Austria, a neighboring country that is a popular destination for smuggled migrants who travel through Hungary from the Balkans to reach the core of the European Union. Vienna said it considers the freeing of human traffickers as a threat to security.

The BvOP press office said in an email that Hungarian prisons had 2,636 people who were sentenced for trafficking humans, and 808 of them were foreign citizens who qualified for the release.

“It costs Hungarian prisons billions of forints every year to keep foreign nationals behind bars,” the press office said.

It added that those who were freed had to leave Hungary’s territory within 72 hours, and if they were caught by police without doing so, they would have to serve their full sentence in prison.