During the Vietnam War of the 1960s and 1970s, Japan consistently encouraged a negotiated settlement at the earliest possible date. Even before the hostilities ended, it had made contact with the Democratic Republic of Vietnam (North Vietnam) government and had reached an agreement to establish diplomatic relations in September 1973. Implementation, however, was delayed by North Vietnamese demands that Japan pay the equivalent of US$45 million in World War II reparations in two yearly installments, in the form of "economic cooperation" grants. Giving in to the Vietnamese demands, Japan paid the money and opened an embassy in Hanoi on October 11, 1975, following the unification of North Vietnam and South Vietnam into the Socialist Republic of Vietnam. Recognition of the communist Khmer Rouge regime in Cambodia came in 1975, and diplomatic relations with that country were established in 1970s.