(S (S (BASENP (NNP Prime) (NNP Minister) (NNP Vladimir) (NNP Putin)) (VP (VP (VBD said) (PP (IN on) (BASENP (NNP Wednesday)))) (SBAR (IN that) (S (BASENP (DT the) (NN attack)) (VP (VP (VBZ is) (RB not)) (VP (VBN thought) (S (VP (TO to) (VP (VB be) (VP (VBN linked) (PP (TO to) (BASENP (NNP Chechnyan) (NN insurgency))))))))))))) (PERIOD .))