In 2016, the Hungarian government implemented several security counter-measures at its southern borders -- raising security fences, ordering non-stop patrolling by joint forces of the National Police and military -- to prevent waves of migrants from entering the country illegally. The counter-measures were a success, and migrants, primarily from the Middle and Far East, were stuck in the Balkans (Serbia). Many who circumvented border defenses were captured by Hungarian police and military forces and escorted back to Serbia. Most migrants/refugees crossing the border intend to transit Hungary en route to Germany and Western Europe. Investigative evidence showed terrorists arrived hidden within the large, uncontrollable immigrant wave of 2015. The Hungarian government reported that following the erection of the technical border defense systems and non-stop patrolling at the border no terrorists have entered the Schengen zone through Hungary. Furthermore, the Hungarian government has started to further strengthen the border defense system by erecting a second fence line, installing a heat sensor system, and a 3,000-person newly recruited and trained independent border guard police force have been stationed permanently at the borders.