The Kingdom of Cambodia became a republic, that was formally declared in October 1970. The Khmer Republic was headed by General Lon Nol that took power in the 1970 coup against Prince Norodom Sihanouk.The Khmer Republic was the pro–US military-led country. The Song of the Khmer Republic (Khmer: បទចម្រៀងនៃសាធារណរដ្ឋខ្មែរ) was the national anthem of the Khmer Republic. It was adopted as the national anthem after the overthrow of the monarchy.