BUDAPEST, Hungary (AP) – A security guard fired three warning shots when several dozen migrants tried to enter Hungary Tuesday through a border crossing with Serbia, Hungarian police said.

Police said they were able to stop most of the 60-70 migrants from entering Hungary, while four were caught at the scene and detained.

The border crossing at the southern village of Roszke had been closed for the night when the attempt occurred.

Officials described the incident, which took place at the same location as a September 2015 riot by migrants when Hungary closed its southern border with fences protected by razor wire, as an “extraordinary and violent” attempt to breach the border.

Hungarian authorities have been pointing to a noticeable increase in past months in the number of migrants coming north through the Balkans and trying to enter Hungary. Many rely on human traffickers and are trying to make their way to Western Europe.