(S (S (ADVP (RB Later)) (COMMA ,) (S (BASENP (NNP Mottaki)) (VP (VP (VBD stated) (SBAR (IN that) (S (BASENP (NNP Iran)) (VP (VBZ believes) (SBAR (IN that) (S (NP (BASENP (DT the) (NN presence)) (PP (IN of) (BASENP (JJ American) (NNS troops)))) (VP (VBZ is) (NP (BASENP (DT the) (NN source)) (PP (IN of) (BASENP (NN instability))))))))))) (CC and) (VP (VBD called) (PP (IN for) (NP (BASENP (DT the) (NN withdrawal)) (PP (IN of) (BASENP (JJ American) (NNS troops))))))))) (PERIOD .))