New developments in the Barcelona terror investigation.

Officials say a terror cell of 12 people had been planning to trigger a number of bombs by packing vehicles with gas canisters.

The driver of the van used on the Las Ramblas attack remains on the loose, while four other members of the cell remain unaccounted for.

UK Correspondent Gavin Grey told Rachel Smalley seven year old Australian boy Julian Cadman has been confirmed as one of those killed.

"This attack, the more you look at it, id definitely targeted not at the Spanish, it was targeted at the western world in general."

The terror cell aborted its bombing plans when the house it was using to make bombs exploded.

LISTEN ABOVE AS GAVIN GREY SPEAKS WITH RACHEL SMALLEY