Prime Minister KP Sharma Oli has resigned amid Nepal's worst unrest in decades, as public anger mounts over the deaths of 19 anti-corruption protesters in clashes with police on Monday.

Prime Minister K.P. Sharma Oli stepped down as large crowds defied an indefinite curfew in Kathmandu and other cities.

Fire rages through the Singha Durbar, the main administrative building for the Nepali government, in Kathmandu on Tuesday, a day after a police crackdown on demonstrations over social media prohibitions and corruption by the government.