The Nazis deported the Dutch Jews to concentration and extermination camps. They started building fortifications along the coast and constructed 30 airfields. They forced adult males between 18 and 45 to work in German factories or on public work projects. In 1944, most trains were sent to Germany and 550,000 Dutch people were sent to Germany as laborers. Resistance became better organized and more forceful. The resistance killed high-ranking Dutch officials, such as General Seyffardt.