Whilst the war in Indochina was being fought between the Vietnamese and the French, Thailand – disliking both her old rivals equally – initially refrained from entering the conflict, but once it became a war between the US and the Vietnamese Communists, Thailand committed itself strongly to the US side. Thailand concluded a secret military agreement with the US in 1961, and in 1963 openly allowed the use of their territories as air bases and troop bases for US forces before finally sending her own troops to Vietnam. A Royal Thai Volunteer Regiment (the "Queen's Cobras") and later the Royal Thai Army Expeditionary Division ("Black Panthers"), then a brigade, served in South Vietnam from September 1967 to March 1972. Thailand was however more involved with the secret war and covert operations in Laos from 1964 to 1972. The Vietnamese retaliated by supporting the Communist Party of Thailand's insurgency in various parts of the country. By 1975 relations between Bangkok and Washington had soured; eventually all US military personnel and bases were forced to withdraw and direct Thai involvement in the conflict came to an end.