Fanatical gunmen destroyed SAS training establishment (8)

I believe the answer is:

madrassa

'training establishment' is the definition.
(Arabic term for a school)

'fanatical gunmen destroyed sas' is the wordplay.
'fanatical' becomes 'mad' (I've seen this in another clue).
'gunmen' becomes 'RA' (Royal Artillery).
'destroyed' indicates an anagram.
'sas' is an anagram of 'ssa'.
'mad'+'ra'+'ssa'='MADRASSA'

I've seen this clue in The Independent.

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