Take over some of Iran next (5)
I believe the answer is:
annex
'take over' is the definition.
(annexing is a kind of taking over)
'some of iran next' is the wordplay.
'some of' indicates the answer is hidden within the clue.
'ANNEX' is hidden within 'iran next'.
(Other definitions for annex that I've seen before include "Attach after conquest" , "Add as an extra part" , "Attach, invade" , "Tack on" , "Extension to a main building" .)