Their grandmother is still buried under the rubble, with the Italian emergency services trying to find them.

Rescuers in the Naples town of Saviano recovered the bodies of the four- and six-year-old siblings during the operation, and then later recovered their mother.

Their father and two-year-old brother were found alive, although their father is in hospital in a serious condition.

A gas explosion likely caused the collapse, according to the local fire service in a post on Telegram.

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Firefighters spokesman Luca Cari said that rescuers had to be "very careful and move slowly, to avoid new collapses" as they searched for the two women.

Mayor Vincenzo Simonelli was at the scene and told reporters the building appeared "crumpled up on itself," adding it was "a very serious situation".

It appears the gas explosion rocked the second floor of the building which crumpled down, covering the lower floor with rubble.