In the 1970s, both Malaysia and Thailand constructed walls along their common border, mostly in Perlis/Satun and Perlis/Songkhla as well as Kedah/Songkhla portions of the border to curb smuggling. The walls were of concrete and steel and were topped with barbed wire as well as iron fencing at other stretches. As both countries constructed their own walls a little into their own territory, a strip of "no-man's-land" about 10m wide was created and this strip of land became a convenient refuge for smugglers (not all smuggling was deterred by the wall) and drug runners.