(S (NP (NP (BASENP (DT The) (NNP Department)) (PP (IN of) (BASENP (NNP Homeland) (NNP Security)))) (PRN (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VBD issued) (BASENP (DT the) (NNS warnings))))) (COMMA ,))) (VP (VBZ has) (VP (ADVP (RB also)) (VP (VBN added) (SBAR (IN that) (S (BASENP (DT the) (NN threat)) (VP (VBZ is) (QT (DQL ``) (QTC (ADJP (RB not) (JJ credible)) (PERIOD .)) (DQR '')))))))))