Operation Collie
Its objectives were , firstly , naval bombardment and aerial strikes on Japanese positions in the Nicobar Islands , particularly on Nancowry Island; secondly , providing cover for minesweeping operations in advance of a possible invasion; and thirdly , making carrier raids on Japanese airfields in northern Sumatra . 
<triplet> Nancowry Island <subj> Nicobar Islands <obj> part of