Hungarian police say they have discovered two tunnels used by migrants to enter the country from Serbia.

The Hungarian National Police Headquarters said Friday that one tunnel was discovered in the southern village of Asotthalom, where they also detained 44 migrants caught using the precarious passageway.

The other tunnel, in the village of Csikeria, was 21.7 meters (71 feet) long, but no successful migrant crossings took place there. Police said they discovered both tunnels not long after their construction was completed and filled both of them up again.

In this undated photo issued by Hungarian Police, measuring sticks are placed near the entrance to a tunnel in the village of Asotthalom, southern Hungary.  Police said 44 migrants were caught using this tunnel to enter Hungary from Serbia. (ORFKpolice.hu via AP)

In this undated photo issued by Hungarian Police, measuring sticks are placed near the entrance to a tunnel in the village of Asotthalom, southern Hungary. Police said 44 migrants were caught using this tunnel to enter Hungary from Serbia. (ORFKpolice.hu via AP)

In 2015, at the height of the migration crisis, Hungary built razor-wire fences on its southern borders to stem or divert the flow of people, many from the Middle East and Asia, making their way to Western Europe.

In this undated photo handed out by Hungarian Police, wooden boards are placed as camouflage over the entrance to a tunnel in the village of Asotthalom, southern Hungary. Police said 44 migrants were caught using the tunnel to enter Hungary from Serbia. (ORFKpolice.hu via AP)

In this undated photo handed out by Hungarian Police, wooden boards are placed as camouflage over the entrance to a tunnel in the village of Asotthalom, southern Hungary. Police said 44 migrants were caught using the tunnel to enter Hungary from Serbia. (ORFKpolice.hu via AP)