Military conflict observed in Poland (6)
I believe the answer is:
warsaw
'in poland' is the definition.
('Warsaw' is part of 'poland')
'military conflict observed' is the wordplay.
'military conflict' becomes 'war'.
'observed' becomes 'saw' (I've seen this before).
'war'+'saw'='WARSAW'
(Other definitions for warsaw that I've seen before include "Polish capital" , "1929 international agreement regulating commercial air transport" , "Capital city on the Vistula" , "Capital city of Poland" , "Capital of a European Union state" .)