Pakistani firefighters on Monday sifted through the smoldering wreckage of a vast shopping mall in Karachi, searching for more than 60 people still unaccounted for after a massive blaze that killed at least 14.

The fire broke out late Saturday at Gul Plaza, a multistory complex housing about 1,200 shops and spanning an area larger than a football field in the city’s historic center.

Video footage showed towering flames engulfing the building as crews battled through the night to contain the inferno. By Monday, firefighters were cooling the charred structure and clearing mangled metal and debris littering the street, including collapsed air-conditioning units and torn shop signboards.

Rescue teams warned the remaining shell of the building was dangerously unstable and could collapse at any moment.

Hundreds of people surrounded the site to watch the rescue efforts, including shop owners whose life’s work was reduced to ash overnight.