To observers in Phnom Penh, South Vietnam's short-term viability was seriously in doubt, and this compelled a new tack in Cambodian foreign policy. First, Cambodia severed diplomatic ties with Saigon in August 1963. The following March, Sihanouk announced plans to establish diplomatic relations with North Vietnam and to negotiate a border settlement directly with Hanoi. These plans were not implemented quickly, however, because the North Vietnamese told the prince that any problem concerning Cambodia's border with South Vietnam would have to be negotiated directly with the National Front for the Liberation of South Vietnam (NFLSVN). Cambodia opened border talks with the front in mid-1966, and the latter recognized the inviolability of Cambodia's borders a year later. North Vietnam quickly followed suit. Cambodia was the first foreign government to recognize the NFLSVN's Provisional Revolutionary Government after it was established in June 1969. Sihanouk was the only foreign head of state to attend the funeral of Ho Chi Minh, North Vietnam's deceased leader, in Hanoi three months later.