Country seeing nothing held by deserter surrounded by agents (7)
I believe the answer is:
croatia
'country' is the definition.
(I know that Croatia is a European country)
'nothing held by deserter surrounded by agents' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'held by' indicates putting letters inside.
'deserter' becomes 'rat' (both can mean a traitor).
'surrounded by' means one lot of letters goes inside another.
'agents' becomes 'CIA' (Central Intelligence Agency).
'o' put inside 'rat' is 'roat'.
'roat' placed within 'cia' is 'CROATIA'.
'seeing' is the link.
(Other definitions for croatia that I've seen before include "Adriatic nation" , "Balkan country, capital Zagreb" , "Adriatic country" , "European state" , "Balkan republic, capital Zagreb" .)