(S (S (S (BASENP (DT The) (JJ second) (NN attack)) (VP (VBD occurred) (PP (IN within) (NP (BASENP (NNS minutes)) (PP (IN of) (BASENP (DT the) (JJ first))))))) (CONJP (COMMA ,) (CC and)) (S (NP (BASENP (NN four) (NNS militants)) (COMMA ,) (SBAR (WHNP (WP who)) (S (VP (VBD were) (VP (VP (VBG carrying) (PRT (RP on))) (BASENP (NN rescue) (NN work))))))) (VP (VBD were) (VP (VBN killed) (PP (IN by) (NP (BASENP (DT the) (NN two) (NNS missiles)) (SBAR (WHNP (WDT that)) (S (VP (VBD had) (VP (VBN been) (VP (VBN fired)))))))))))) (PERIOD .))