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Cavalry found a new role in colonial campaigns ( irregular warfare ) , where modern weapons were lacking and the slow moving infantry-artillery train or fixed fortifications were often ineffective against indigenous insurgents ( unless the latter offered a fight on an equal footing , as at Tel-el-Kebir , Omdurman , etc . ) .
 Tel-el-Kebir, Omdurman
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Tel-el-Kebir, Omdurman