04/02/2008 (Agence Europe) - Sofia is to invest nearly €160 million in border security in order to join the Schengen space in 2011, the Bulgarian interior minister, Roumen Petkov, announced on Friday 1 February, during a conference on the country's preparation for the enlargement of the border-free zone. Bulgaria has already spent some €77 million on technical infrastructures designed to protect its external borders, which are 1647 km long. (B.C.)