Christodoulos Xiros, a far-left terrorist gunman serving six life sentences, vanished while on New Year's leave from prison, prompting a nationwide manhunt.
Xiros was convicted in 2003, along with two of his brothers, of belonging to the November 17 terrorist group, which killed 23 people including foreign diplomats, policemen and businessmen between 1975 and 2000.
State Department spokeswoman Jen Psaki said yesterday that the US is in touch with Greek officials about the case and is calling on the Greek government to find him and return him to prison.