C.I.A. declassified documents reported that the
border crossing at Walterdorfer strasse opened
in 1963 linking West Berlin to SXF had 180.000
pax using the border crossing in 1970.
Also importantly that Interflug had started a new
service in 1970 which was not announced in any
airline guide (ABC or AOG) nor in the press.
The flight was SXF-Ulaanbataar Mongolia,
The Mongolians established an embassy in GDR
in Karlshorst A relationship existed because of a
similar ideology. The Mongolians opened an Embassy
in the FRG in Troisdorf in 1974.
Lance Shippey