rtokens: U.S. plans rely heavily on U.S. air attacks on Iraqi forces , but there are also 23,000 U.S. troops in the region , according to defense officials .
pos: EX VBD JJ NNS IN NNP VBD VBN NNS IN JJ NNP IN NN TO NNP POS NN .
tokens: There were unconfirmed reports that Iran had sent troops into northern Iraq in response to Iraq 's attack .
ltokens: Clinton said Iraqi military forces overran the city of Arbil , which has been held since 1994 by Kurdish rebels who Baghdad says are backed by Iran .