There are now four confirmed deaths due to the explosion and six-alarm fire caused by a ruptured gas transmission line in San Bruno Thursday evening, a San Mateo County coroner's deputy said Friday morning.

The number currently stands at four, "but I'm sure it could change throughout the day," said Kristine Gamble, a senior deputy coroner.

Gamble said investigators with the coroner's office will be accompanying search and recovery teams who will be going through the site of the explosion and fire today.

The fire has destroyed at least 53 homes and damaged at least 120 more, according to Cal Fire.