operation black lion (15 june – 19 october 1972) was a royal lao government counter-offensive against a people's army of vietnam thrust that cut the kingdom of laos in two at khong sedone during may 1972. two regiments of royalist military irregulars retaliated on 15 june 1972, attacking the communist 39th regiment in an air assault while royal lao air force tactical air strikes hammered the 39th. during the next month, the 39th regiment would suffer an estimated 360 casualties and be rendered ineffective for attacks. on 18 july, they retreated, leaving a rear guard to be overrun.