1972 in the Vietnam War the number of air raids against North Vietnam during all of 1971. Prime Minister Lon Nol declared President of Cambodia. Unlike the former Cambodian leader, Norodom Sihanouk, Lon Nol was a U.S. ally. The U.S. 101st Airborne Division left South Vietnam, the last U.S. ground combat division to be withdrawn from South Vietnam. The Khmer Rouge bombarded with artillery Phnom Penh, the capital city of Cambodia, killing more than 100 civilians. This was the heaviest attack on Phnom Penh since the Cambodian Civil War began in 1970. The United States boycotted peace negotiations in Paris with the North Vietnamese, citing
Treaty of Tartu (Russian–Estonian) Treaty of Tartu (Russian–Estonian) Tartu Peace Treaty (, literally "Tartu peace") or Treaty of Tartu is a peace treaty between Estonia and Soviet Russia signed on February 2, 1920 ending the Estonian War of Independence. The terms of the treaty stated that ""Russia unreservedly recognises"" the independence of the Republic of Estonia "de jure" and renounced in perpetuity all rights to the territory of Estonia. Ratifications of the treaty were exchanged in Moscow on March 30, 1920. It was registered in "League of Nations Treaty Series" on July 12, 1922. Estonia had been a province of Imperial Russia since 1710,