South Africa's president is facing calls to order an inquiry into a police operation that was meant to combat illegal mining but ended up leaving 87 miners to die underground as authorities attempted to force them to surrender during a monthslong standoff.

The clampdown on illegal mining cut off food and water to hundreds of miners underground. At least 78 bodies were pulled from a mining shaft this week, and more are believed to remain underground.

The authorities had at one point limited the miners’ access to food, water and other supplies in a blockade that drew criticism from human rights groups.