The US voiced here Wednesday its deep concern that a Greek convicted terrorist remains at large after he failed to return to jail, calling on the Greek government to locate him. State Department Deputy Spokesperson Marie Harf told reporters "we're obviously deeply concerned that this convicted terrorist remains at large and is now allegedly issuing renewed calls for violence." She affirmed that the U.S. remains "very closely engaged with the Greek officials concerning this case." "We continue to call on the government to do everything they can to locate him and return him to prison," she added. Greek police have launched a nationwide manhunt for convicted far left-terrorist, Christodoulos Xiros, after he failed to report to the authorities while on furlough. In an online video and letter, Xiros announced "once again I have taken the decision to thunder the guerrilla rifle against those who stole our lives and sold our dreams for a profit." Xiros, was serving multiple life terms in prison for attacks carried out by the group known as "November 17" that killed dozens of people, including Greek politicians, businessmen and British, American and Turkish foreign diplomats and military officials from 1975 to 2000.