A quarter of the homes burned in an enormous blaze sparked after a gas line ruptured are still too hot to search for victims, fire officials said tonight.

A massive blast triggered by a suspected gas leak killed at least four people and destroyed more than 50 houses in a neighbourhood near San Francisco today.

At least one person was killed and more than 50 homes destroyed when a huge explosion sent flames roaring through a neighbourhood in hills south of San Francisco, California fire chiefs said today.

A lawyer who tried to extort $310,000 from Erin Brockovich and her boss has been sentenced to four months in jail.