Bulgaria would build a 30-km fence along its border with Turkey amid unprecedented wave of refugees, an official said here on Wednesday. The fence was designed to increase the level of security at the border in a section where 85 percent of refugees have entered the country, Vasil Marinov, Deputy Minister of Interior told reporters. Since the beginning of the year, Bulgarian security forces have detained more than 6,500 people who have entered the country illegally, almost all of them at the land border with Turkey. During the Cold War, Bulgaria built 143 km of barbed wire fence to protect its 210-km-long border with Turkey but removed most of this fence after joining NATO in 2004.