Tens of thousands of Cambodians packed a stadium in Phnom Penh Monday to celebrate the 40th anniversary of the expulsion of the brutal Khmer Rouge regime — a day strongman Prime Minister Hun Sen called the country’s “second birthday”.

The ultra-Maoist Khmer Rouge, led by Pol Pot, installed a reign of terror in 1975 that left two million Cambodians dead from starvation, hard labour, torture and mass executions.

It ended on January 7, 1979, when Hun Sen, a former Khmer Rouge cadre, led Vietnamese forces into the capital to expel the murderous regime.

The 66-year-old premier hailed the day as Cambodia’s “second birthday” at an elaborate ceremony in Phnom Penh’s Olympic Stadium, where he was joined by traditional Khmer apsara dancers and marching bands.