March 24, 1971 (, Xinhai February 28), the failed attempt of South Vietnamese invasion of Laos.

1971, 24, in the Communist army struggling to resist (? v history today?? com) South Vietnam was forced to advance to the end of military action to cut off the enemy supply lines in Laos.
South Vietnamese troops into Laos in the U.S. Air Force and artillery support, 44 days after the announced withdrawal of troops. The purpose of the military action is to destroy the communist forces known as the Ho Chi Minh Trail supply line. In the most intense fighting when the South Vietnamese army in Laos reached 20,000. South Vietnamese forces suffered heavy casualties: 1,146 soldiers were killed. The United States has lost 89 helicopters, 51 American soldiers were killed.